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Heredity and Evolution - Lakhmir Singh Manjit Kaur Solutions Pg No. 195 Class 10 Biology

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Solutions of Heredity and Evolution Lakhmir Singh Manjit Kaur HOTS, VSAQ, and SAQ Pg No. 195 Class 10 Biology

Solutions of Heredity and Evolution Lakhmir Singh Manjit Kaur HOTS, VSAQ, and SAQ Pg No. 195 Class 10 Biology

Questions Based on High Order Thinking Skills (HOTS)-Pg-195

66. In humans, if gene B gives brown eyes and gene b gives blue eyes. What will be the color of eyes of the persons having the following combination of genes?
(a) Bb (b) bb (c) BB

Answer

→ (a)Bb-Brown eyes.(B is dominant which gives brown eyes)
(b)bb-Blue eyes.(b is recessive which gives blue eyes and none dominant gene present)
(c)BB-Brown eyes.(B is dominant which gives brown eyes)

67. Pure-bred pea plants A are crossed with pure-bred pea plants B. It is found that the plants which look like A do not appear in F1 generation but re-emerge in F2 generation. Which of the plants A and B are : (i) tall, and (ii) dwarf? Give reason for your answer.

Answer

→ (i) tall- B plant
(ii) dwarf- A plant.
This is because only tall plants appear in the F1 generation and dwarf plants appear in the F2 generation along with tall plants.

68. Pure-bred tall pea plants are first crossed with pure-bred dwarf pea plants. The pea plants obtained in F1 generation are then cross-bred to produce F2 generation of pea plants.
(a) What do the plants of F1 generation look like ?
(b) What is the ratio of tall plants to dwarf plants in F2 generation?
(c) Which type of plants were missing in F1 generation but reappeared in F2 generation?

Answer

→ (a) Tall plants
(b) 3:1
(c) Dwarf plants.

69. A plant has two varieties, one with red petals and the other with white petals. When these two varieties are cross-pollinated, all the offspring have red petals?
(a) Which gene is dominant?
(b) Choose suitable letters to represent the two genes.

Answer

→ (a) Red color (Dominancy means ruling over the other)
(b) R and r (R for Dominant and r for recessive)

70. A red-haired woman marries a brown-haired man, and all the children are brown haired. Explain this genetically.

Answer

→ Brown hair color genes are dominant and the red hair color genes are recessive ; The genotype of brown hair is BB (dominant always represented by capital letter) and that of red hair bb (Recessive represented by small letter)

71. A black mouse mates with a brown mouse, and all the offspring are black
(a) Why are no brown off springs produced?
(b) If two of the black offspring mate with each other what kind of offspring would you expect and in what proportions? Give reason for your answer.

Answer

→ (a) No brown offspring are produced because brown color is recessive here and black being dominant rules.
(b)Three black mice and one brown mouse will be obtained in F2 generation; It is a monohybrid cross(Punett Square)

72. (a) E is the gene for brown eye color and e is the gene for blue eye color. Which gene is
(i) Recessive, and
(ii) Dominant
(b) Both father and mother have the genes Ee in their cells. What color are their eyes?
(c) Which combination of genes in the zygote will produce children with blue eyes?
(d) Which combinations of genes in the zygote will produce children with brown eyes?

Answer

→ (a) (i) e blue color gene is recessive; recessive is always represented by small letters.
(ii) E brown color gene is dominant; dominant is always represented by capital letters.
(b) They have brown eye color because dominant gene for brown eye color is present which suppresses the recessive gene for blue eye color and hence brown eye color is expressed
(c) Combination of ee will produce children with blue eyes because for blue eye color to be expressed there should not be gene for brown eye color that is E because if E gene will be present it will dominate the eye color and then brown eye color will be expressed and if there will be no dominant gene i.e. ee then the eye color expressed will be blue.
(d) The combinations EE and Ee will produce children with brown eyes because for brown eyes to be expressed there must be at-least one dominant gene for brown eye color i.e. E be present.

73. What are the possible blood groups likely to be inherited by children born to a group A mother and a group B father? Explain your reasoning.

Answer

→ The possible genotype that will be inherited by the children when the mother is group A and the father is group B are IA IB, IA IO, IB IO and IOIO. The possible blood group likely to be inherited will be either AB,A,B and O.


74. A couple with a newborn baby is troubled that the child does not resemble either of them. Suspecting that a mix-up occurred at the hospital, they check the blood type of the infant. It is type 0. Because the father is type A and the mother type B, they conclude that a mix-up has definitely occurred. Are they correct? Give reason for your answer.

Answer

→ No, the parents are not correct. The father is type A and the Mother is type B; the possible genotypes that are inherited by the baby are IA IB, IA IO, IB IO and IOIO. This means that any of the blood type AB, A, B, and O can be inherited by the child. If the child inherits any of the one blood type, which is occurring here in this case that the child is inheriting type O blood group, no error has occurred.

75. A man with blood group A marries a woman with blood group 0 and their daughter has blood group 0. Is this information enough to tell you which of the traits - blood group A or 0 -is dominant? Why or why not?

Answer

→ Case 1: Man with blood group A married a woman with blood group B. Blood group for man can be expressed by dominant genotype IAIA orIAIO and blood group O for woman is expressed by recessive genotype IOIO. The daughter will have O blood group type as a result of this IOIO inheritance of recessive traits from mother and father.
Case 2: Blood group A in father if has recessive genotype IAIA and mother has dominant genotype IAIO or IOIO. The daughter will have O blood type as a result of inheritance of dominant allele IO from mother and recessive allele IA from father.
Blood group A is expressed in both homozygous and heterozygous condition but Blood group O is expressed in recessive condition.

76. A Mendelian experiment consisted of breeding tall TT pea plants bearing violet flowers with short t pea plants bearing white w flowers. The progeny all bore violet W flowers, but almost half of them were short. This suggested that the genetic make-up (or genotype) of the tall parent can be depicted as:
(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw
Give reason for your choice

Answer

→ The genetic makeup of the tall parent can be depicted as (C) TtWW. As the question says, Tall Pea plants bearing violet flowers; Tallness is a dominant trait and is always represented by capital letters so ‘T’ and short/dwarfness is represented by small letters so ‘t’ – hence Tt. Violet Flowers is a dominant trait and is represented by capital letters so ‘W’. The progeny had short plants but no white flowers which means that Violet flowers are being passed on. Therefore, the genotype of the tall parent can be depicted as TtWW. There is a dominant gene for tallness which suppresses the recessive gene for height and for all violet flowers were present in tall pea plant.

77. A person first crossed pure-bred pea plants having round-yellow seeds with pure-bred pea plants having wrinkled-green seeds and found that only A-B type of seeds were produced in the F1generation. When F1 generation pea plants having A-B type of seeds were cross-bred by self-pollination, then in addition to the original round-yellow and wrinkled-green seeds, two new varieties A-D and C-B type of seeds were also obtained.
(a) What are A-B type of seeds?
(b) State whether A and B are dominant traits or recessive traits.
(c) What are A-D type of seeds?
(d) What are C-B type of seeds?
(e) Out of A-B and A-D types of seeds, which one will be produced in
(i) minimum numbers, and
(ii) maximum numbers, in the F2 generation ?

Answer

→ (a)Round Yellow.
Round yellow- RRYY, wrinkled green-rryy. On crossing these two pea plants we get RrYy combination which has dominant gene R for Round shape and Dominant gene Y for yellow color. Hence A-B types of seed produced as a result of the first cross are Round yellow.
(b) A and B are dominant traits since they are Round (R) and yellow (Y)
(c) Round-green
When RrYy obtained in the first generation is self-pollinated, the new varieties obtained are RY, Ry, rY, ry; where RY- Round yellow, Ry-Round green, rY-Wrinkled yellow, and ry- wrinkled green. Since A-B type of seed is Round and yellow, therefore A-D type of seed is Round and Green.
(d) Wrinkled-yellow
When RrYy obtained in the first generation is self-pollinated, the new varieties obtained are RY, Ry, rY, ry; where RY- Round yellow, Ry-Round green, rY-Wrinkled yellow, and ry- wrinkled green. Since A-B type of seed is Round and yellow, therefore C-B type of seed is wrinkled and yellow.
(e)(i) A-D (Round and green ‘Ry’ will be produced in minimum number)
(ii) A-B (Round and yellow ‘RY’ will be produced in maximum number in F2 generation)

78. The person A has only B chromosomes in all its gametes. On the other hand, another person C has chromosome D in half of gametes and chromosome E in the other half of gametes. When chromosomes B and D combine during fertilization, a female zygote results. On the other hand, combination of B and E chromosomes produces a male zygote.
(a) What are chromosomes?
(i) B
(ii) D, and
(iii) E ?
(b) Out of B, D and E, which two chromosomes are of the same type?
(c) Which chromosome is smaller in size?
(d) What is the general name of chromosomes such as B and E?
(e) Out of the two persons A and C, which one is
(i) male, and
(ii) female ?

Answer

→ (a) (i) The chromosome B are X chromosomes because if person A is entirely madeup of B chromosomes it means the person is a female an has all X chromosomes.
(ii) The chromosome D is X chromosome again because when B and D combine a female offspring is produced. A female zygote can only be produced when both of the chromosomes in the gamete are ‘X’. Chromosome B is X as already said above; now chromosome D is also X. Thus only then when B and D chromosome i.e. X and X chromosome combine, a female zygote is produced.
(iii) The chromosome E is a Y chromosome because when B and E combine a male zygote is produced. B is a X chromosome as discussed above and when E i.e. Y chromosome combine , a male zygote is produced(XY)
(b) Chromosome B and D are of the same type, i.e. X chromosome.
(c) Chromosome E is smaller in size since it is a Y chromosome.
(d) Chromosome B (X) and chromosome E (Y) are known as Sex Chromosomes
(e) (i) C is male since it has half genes from D and half genes from E.
D is a X chromosome and E is a Y chromosome so when they combine a male zygote is formed.
(ii) A is female since it has all B chromosomes in it i.e. X chromosome which is only possible in female.

79. Mendel first crossed pure-bred pea plants having round-yellow seeds with pure-bred pea plants having wrinkled-green seeds and found that only round-yellow seeds were produced in the F1 generation. When F1 generation pea plants having round-yellow seeds were cross-bred by self-pollination, then peas having round � yellow seeds, round green seeds, wrinkled-yellow seeds and wrinkled-green seeds were produced. Mendel collected a total of 2160 seeds.
(a)What will be the number of?
(i) Round green seeds
(ii) Wrinkled green seeds
(iii) Round yellow seeds, and
(iv) Wrinkled-yellow seeds
(b) Which 'ratio' as established by Mendel have you made use of in answering the part (a) above?

Answer

→ (a) The F2 generation obtained had Round yellow: Round green: Wrinkled yellow: Wrinkled green in the ratio 9:3:3:1
(i) Round Green seeds- (3/16)*2160= 405
(ii) Wrinkled Green seeds- (1/16)*2160= 135
(iii) Round yellow seeds- (9/16)*2160= 1215
(iv) Wrinkled yellow seeds- (3/16)*2160= 405
(b) Dihybrid ratio has been used in answering this question because here are two different varieties, that differ in two observed traits i.e. Shape : round and wrinkled; Color: yellow and green.

80. Pure-bred round-yellow pea seeds have genotype RRYY and the pure-bred wrinkled-green pea seeds have genotype rryy. Keeping this in mind, write the phenotypes of the following genotypes of hybrid pea seeds:
(a) Rryy
(b) rrYy
(c) rrYY
(d) RrYy
(e) RRyy

Answer

→ (a) Round-green (RR-round; dominant, yy-green; recessive)
(b) Wrinkled-yellow (rr-wrinkled; recessive, Yy- since one dominant gene Y Is present- yellow)
(c) Wrinkled-yellow (rr-wrinkled; recessive, YY-yellow, dominant)
(d) Round-yellow (Rr-one gene dominant R is present-round; Yy- since one dominant gene Y is present- yellow)
(e) Round-green(RR-round; dominant, yy-green; recessive)

Very Short Answer Type Questions-Pg-208

1. What name is given to the sequence of gradual changes over millions of years in which new species are produced?

Answer

→ Evolution is the process of gradual changes in heritable characteristics over long time which leads to the formation of new species. These new species develop from their earlier forms during time.

2. Name the scientist who gave the theory of evolution.

Answer

→ Charles Robert Darwin gave the theory of evolution in his book ‘Origin of Species’ by means of Natural Selection.

3. State whether the following statement is true or false: Human beings have evolved from chimpanzees.

Answer

→ The given statement is False. Human beings are more closely related to modern apes but did not evolve from them too. Human beings just share a common ancestor with modern African apes like gorillas and chimps but did not evolve from them.

4. State one characteristic which shows that birds are very closely related to dinosaurs.

Answer

→ A feature that is common to both birds and dinosaurs is presence of feathers on their body which shows that birds and dinosaurs are closely related. Dinosaurs had feathers but they could not fly and birds used feathers to provide insulation to their bodies in harsh weather but later on the feathers became useful for flying.

5. Name an animal having rudimentary eyes.

Answer

→ Flatworm – Planaria has rudimentary eyes as eye spots.

6. Name the ancestor of the following: Broccoli, Kohlrabi, Kale.

Answer

→ All the three, Broccoli, Kohlrabi and Kale have a common ancestor that is wild cabbage.
Plant parts of Wild cabbage or Brassica oleracea are modified by artificial selection to produce these varieties of cabbage
Flower buds and stem are modified-Broccoli
Stem is modified- Kohlrabi
Leaves are modified- Kale

7. Where did life originate on the earth?

Answer

→ It is believed that life originated in sea water, near deep sea hydrothermal vents.

8. Write the names of at least three inorganic molecules which helped in the origin of life on the earth.

Answer

→ Methane, Ammonia and Hydrogen Sulphide are the three inorganic molecules that helped in origin of life on earth. Stanley Miller and Harold Urey performed experiments that showed that organic compounds could b synthesized by stimulating conditions of the early earth atmosphere.

9. Name the famous book written by Charles Robert Darwin.

Answer

→ Charles Robert Darwin wrote the book “Origin of Species” in which he gave theories of Evolution.

10. The forelimbs of a frog, a bird and a man show the same basic design (or basic structure) of bones. What name is given to such organs?

Answer

→ Organs that are similar in structures are known as homologous organs because they have basic design of bones but they have different functions. Forelimbs of frog are used to prop up the front ends of the body when at rest, forelimbs of bird are used for flying, and forelimbs of man are used for grasping.

11. Name two organisms which are now extinct and studied from their fossils.

Answer

→ Two organisms that are now extinct and studied from their fossils are Dinosaurs and Archaeopteryx lithographica.
Dinosaurs are believed to be ancestors of birds. Archaeopteryx is link between reptiles and birds.

12. Out of the wing of a bird, wing of an insect and the wing of a bat:
(a) Which two are homologous organs?
(b) Which two are analogous organs?

Answer

→ (a) Wing of a bird and wing of a bat are homologous organs. They are homologous with their forelimbs which they inherit from common ancestor.
(b) Wing of an insect and wing of a bird are analogous organs. They perform the same function of uplifting the body in air but their basic structure is totally different.

13. Why are human beings who look so different from each other in terms of size, color and looks said to belong to the same species

Answer

→ This is because human beings reproduce. There are no geographical barriers so they interbreed easily and produce viable offspring. It is the result of variations that human beings look different from each other in terms of size, color and looks.

14. Name five varieties of vegetables which have been produced from 'wild cabbage' by the process of artificial selection.

Answer

→ Brassica oleracea (wild cabbage) is modified by artificial selection to produce many varieties of vegetables. 5 of such varieties are- Broccoli, Kohlrabi, Kale, Cabbage and Cauliflower.

15. Choose the one term from the following which includes the other three: broccoli, wildcabbage, cauliflower, cabbage.

Answer

→ Various plant parts of Wild Cabbage (Brassica oleracea) are modified by artificial selection to give broccoli, cauliflower and cabbage. Thus, Wild cabbage includes the other three.

16. Fill in the following blanks with suitable words:
(a) The human forelimb and bat's forelimb are examples of..................... organs whereas an insect's wing and a bat's wing are an example of ..................... organs.
(b) The evolution of eye is an example of evolution by .....................
(c) The scientific name of all human beings is....................
(d) Broccoli has evolved from ..................... by the process of artificial selection.
(e) The theory of natural selection for evolution was proposed by……………..

Answer

→(a) Homologous organs; Analogous organs.
(Homologous organs are those which have a similar structure; whereas analogous organs are those which have a similar function).
(b) Stages.
(c) Homo Sapiens
(Modern specie of humans is Homo Sapiens). Homo sapiens evolved between 250,000 and 100,000 years ago in Africa.
(d) Wild cabbage (Brassica oleracea)
(Flower buds and stem are modified traits to produce Kohlrabi)
(e) Charles Robert Darwin.
(Darwin proposed the theory of evolution in his book “Origin Of species”, by means of Natural Selection.

Short Answer Type Questions-Pg-209

17Match the terms given in column I with those given in column II :

Column IColumn II
(i) Fossil(a) A famous evolutionist
(ii) A theory of evolution(b) Survival of the fittest
(iii) Probable ancestor of bird(c) Petrified remains of prehistoric life
(iv) Charles Darwin(d) Father of genetics
(v) Gregor Mendel(e) Archaeopteryx


Answer

→ (i) c – petrified remains of prehistoric life
(Dead remains of animals and plants that petrified under environmental conditions over millions of years)
(ii) b – Survival of the fittest
(Evolution occurs over years by the process of natural selection which is based on survival of the fittest)
(iii) e - Archaeopteryx
(Archaeopteryx is a fossil that had been found and studies revealed that it is a fossil of bird since it had avian features)
(iv) a- a famous evolutionist
Charles Darwin wrote the book “Origin of species”
(v) d- father of genetics
Gregor Mendel is the father of genetics.

18. What is meant by acquired and inherited traits? Explain with one example each.

Answer

→ Acquired traits are not inherited by the organism genetically but by environmental conditions present around the organism or the environmental conditions in which the organism lives. For example, Beetles will reduce in weight if not given enough food.
Whereas,
Inherited traits are those characteristics that an organism inherits from his/her parents i.e., passed on genetically through DNA. (Change in DNA). For example –Change of beetles in color from red to green.

19. Why are the traits acquired during the life time of an individual not inherited?

Answer

→ A trait can be only inherited when it brings a change in genes present in the gametes of an organism. Changes in non-reproductive tissues cannot be passed on to DNA of germ cells. Therefore traits acquired during lifetime of an individual are not inherited by the offspring because they are changes in somatic cells and not in germ cells.

20. Can the wing of a butterfly and the wing of a bat .be considered homologous organs? Why or why not?

Answer

→ No, the wings of a butterfly and the wings of a bat cannot be considered homologous organs because they don’t have similar basic structure, even if they perform similar functions i.e. flying. The wings of bat are supported by bones whereas the wing of a butterfly has no bones but is supported by membranous folds which are attached with muscles and not bones. Wings of a butterfly and wings of a bat are analogous organs which have similar functions but different origins.

21. Name two animals having homologous organs and two having analogous organs. Name these organs.

Answer

→ Homologous organs are found in humans and lizards. The forelimbs of humans and lizards have different functions completely but the basic structure of bones is similar, i.e. they have same origin. Another example is forelimbs of frog and forelimbs of humans.
Analogous organs are found in bat and butterfly. The wings of a bat and wings of a butterfly have similar function i.e. flying but they have completely different origin.
Another example is wing of an insect and wing of a bird.

22. What are fossils? Giving one example, explain how fossils provide evidence for evolution.

Answer

→ Fossils are the dead remains of plants and animals which undergo several physical and chemical processes after they are dead.
Example- Archaeopteryx lithographica is a fossil that resembles a bird(has feathers and wings) but has several features of reptiles(tail and teeth) . So Archaeopteryx is supposed to be the connecting link between aves and reptiles thus suggesting that birds have evolved from reptiles.

23. Give an example of characteristics being used to determine how close two species are in evolutionary terms.

Answer

→ If different organisms have common ancestors then it is possible that they have similar characteristics due to inheritance. These similarities are used to determine their close relations in evolutionary terms. For example – forelimbs of bird and forelimb of humans have similar basic structure of bones which suggests that they have a common ancestor i.e. they are closely related in evolutionary terms. Over time these structures have developed to function as per the requirement. Thus homologous organs help in determining closeness in evolution.

24. In what way is homologous organs evidence for evolution?

Answer

→ Homologous organs are the organs that have different functions but they are believed to have originated from a common ancestor because of their basic structure of bones. Thus if homologous organs are present in different organisms, it can be inferred that they have same ancestors which provide evidences for evolution.
Example- forelimbs of humans and forelimbs of frog; they have different functions but they have same basic design which tells that they have a common ancestor.

25. Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?

Answer

→ Small numbers of surviving tigers are a cause of worry from the point of view of genetics because if all the tigers in the world die and become extinct, their genes will be lost forever, they will not come into sight ever again if they become extinct.

26. Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually?
Give reason for your answer.

Answer

→ No; Asexual reproduction is a reproduction wherein an organism does not require another organism to reproduce i.e. there is no fusion of gametes. There is very little variation over generations. Thus, geographical isolation cannot be a major factor in the speciation of an organism that reproduces asexually since variations in DNA are not enough to raise a new species.

27. Name the various tools of tracing evolutionary relationships which have been used for studying human evolution.

Answer

→ •Carbon dating is determination of age by studying relative proportion of carbon isotopes.
•Excavating,-Digging the earth.
•Determining DNA sequences and fossil studies
These are some of the techniques that are being used to study evolution.

28. Out of bacteria, spider, fish and chimpanzee, which organism has a better body design in evolutionary terms? Give reason for your answer.

Answer

→ Bacteria has a better body design in evolutionary terms because they can survive hot springs, deep sea and even freezing environment which most of the other organisms cannot.

29. With the help of an example, explain how variation leads to evolution.

Answer

→ Large Variations occur when organisms reproduce sexually. Variations refer to changes in the genetic material of a population. Those which are useful for the population and help in survival are selected by process of natural selection. The accumulation of these variations over time leads to the development of new species. Asexual reproduction brings about very less variation and hence it causes no evolution.
For example- animals that reproduce sexually like birds. If birds with long beaks and few birds with short beaks inhabit a new area which has food that can be eaten only with short beaks. Birds with short beaks will have greater survival chances in such an area and hence they will reproduce more, thus increasing their number and evolving.

30A. What is meant by a species ? Give two examples of plant species and two of animals.

Answer

→ (A) A species refers to a group of organisms consisting of similar individuals capable of exchanging genes (interbreeding)
Example
•Plant species- Wheat, Daisies, Conifers, etc.
•Animal species- Cow, Dog, Elephant, etc.

30B. State the various factors which could lead to the formation of new species.

Answer

→ (B) Various factors that could lead to formation of new species are Geographical barrier, natural selection and genetic drift.
•Geographical barrier- if sexually reproducing organisms are isolated by geographical barriers then the gene flow through gametes stops and the isolated members interbreed thus leading to the formation of new species.
•Natural Selection- Nature selects individuals that are better adapted to the environment. The organisms that are better adapted survive and reproduce more, whereas the organisms that are not adapted well to the environmental conditions are slowly erased from the environment.
•Genetic drift- genetic drift is changes in the relative frequency of particular genes which leads to disappearance of those genes as individuals either die or they do not reproduce.

31. What evidence do we have for the origin of life from inanimate matter (lifeless matter)?

Answer

→ The evidence for the origin of life from lifeless matter was given by Stanley Miller and Harold Urey in 1953. They recreated the probable conditions of primitive atmosphere of early earth and demonstrated that simple organic compound like amino acids, hydroxyl acids, sugars and urea can by synthesized in the laboratory from a mixture of methane, hydrogen, water vapour and ammonia. They supplied energy by heating the chamber containing the above mixture to 800 degree C and discharges by electric sparks. After about one week, the liquid was found to contain a number of amino acids such as glycine, alanine and aspartic acid.

32. Does geographical isolation of individuals of a species lead to the formation of a new species? Provide a suitable explanation for your answer.

Answer

→ Geographical isolation of a species will lead to the formation of a new species if the species reproduces sexually because isolation will stop the gene flow between the isolated populations since they will not be able to reproduce. As a result, the members of isolated populations will interbreed, leading to the formation of new species.
On the other hand if species that reproduce asexually are geographically isolated, there will be no formation of a new species because such species do not need fusion of gametes to reproduce, they reproduce on their own. Hence there will be no formation of a new species.

33. Bacteria have a simpler body plan when compared with human beings. Does it mean that human beings are more evolved than bacteria? Explain your answer.

Answer

→ Since bacteria have a simpler body plan when compared with human being it does not mean that human beings are more evolved. Bacteria do have a simpler body plan but they have ability to survive harsh environmental conditions/ unfavorable habitats such as high temperature, deep sea hydrothermal vents and freezing temperatures as well. Human beings are also well adapted to the environment they live in. Both, bacteria and human beings have evolved differently.

Heredity and Evolution - Lakhmir Singh Manjit Kaur Solutions Pg No. 210 Class 10 Biology

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Solutions of Heredity and Evolution Lakhmir Singh Manjit Kaur LAQ, MCQ and HOTS Pg No. 210 Class 10 Biology

Solutions of Heredity and Evolution Lakhmir Singh Manjit Kaur LAQ, MCQ and HOTS Pg No. 210 Class 10 Biology

Long Answer Type Questions-Pg-210

34A. Name the scientist who gave the theory of origin of life on earth. What is this theory?

Answer

→ (A) The theory of origin of life on earth was given by J.B.S Haldane.

The theory states that life developed from simple inorganic molecules (methane, ammonia hydrogen sulphide). Haldane said that the conditions on earth at that time including lightning converted these simple inorganic mol.to complex organic molecules that joined together to form the first primitive life forms.

34B. How are those species which are now 'extinct’ studied?

Answer

→ (B) Those species that are now extinct are studied by excavating (digging the earth) and studying their fossils.

35. What do you understand by the term 'evolution'? State Darwin's theory of evolution.

Answer

→ Any change in the heritable characteristics of biological population over successive generation is known as Evolution.
Darwin’s theory of evolution – Natural Selection
Variation occurs within a population. Although Species produce a great number of offspring yet the population number remains the same. This constancy in the population number is because of the struggle for resources like food, shelter etc. This Is known as struggle for existence. It favors the fit individuals which survive and reproduce and eliminates the unfavorable ones. This is Natural Selection. These variations accumulate together and they form a new species over time.

36A. Explain the terms 'analogous organs' and 'homologous organs' with examples.

Answer

→ (A) Analogous organs are organs that are similar in function but have different basic structure which means that they have different origin. For example- Wings of a bird and wings of a bat are analogous organs which have same function of flying but have different basic structure of wings.
Homologous organs are organs that have different functions but have similar basic structure i.e. they have common origin. For example- Forelimbs of man and Forelimbs of frog are similar in structure but they perform completely different functions. Forelimbs of frog are used to prop up at front ends while at rest whereas forelimbs of human are used for grasping.

36B. In what way is analogous organ evidence for evolution?

Answer

→ (B) Analogous organs have similar functions but different origins. Presence of analogous organisms in individuals provides evidence for convergent evolution wherein different organisms with different origins evolve to perform similar functions to adapt to similar environmental niches.

37A. Define 'speciation'. Explain how speciation occurs.

Answer

→ (A) Speciation is the formation of new and different species from existing species in the course of evolution. Speciation occurs when a population gets separated geographically.

37B. Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Give reason for your answer.

Answer

→ (B) No, geographical isolation will not be a major factor in the speciation of a self-pollinating species because self-pollinating plants do not require any other plant to reproduce. Hence, No new gene variants will be introduced into the population and thus there will be no evolution of new species

38A. Define 'natural selection'.

Answer

→ (A) Natural Selection – This theory was given by evolutionist Charles Robert Darwin
Natural selection is a process by which organisms that are better adapted to the environment with their characteristics- survive, reproduce and pass their characteristics to their offspring and organisms that are not adapted well to the environment do not survive much due to the requirements that they fail to accomplish and hence their characteristics are not passed on.

38B. "Only variations that confer an advantage to an individual organism will survive in a population". Do you agree with this statement? Give reason for your answer.

Answer

→ (B) Yes; only variations that confer advantage to an individual organism will survive in a population.
For example- In a population of red beetles, some sudden variation in reproduction produces a green colored beetle. Red beetles are a easy source of prey as they can be easily spotted on the green bushes. The green colored beetle that was produced by a variation could mix up with the green bushes and protect itself from being a prey to predator. If the variation that has occurred in the color of the beetle was blue, then it would have been of no advantage to help in surviving, as it would be easily open to predation like the red beetles.

Multiple Choice Questions (MCQs)-Pg-210

39. In evolutionary terms, we have more in common with:
A. A Chinese school boy
B. A chimpanzee
C. A spider
D. A bacterium

Answer

→ A Chimpanzee is more common in evolutionary terms. Since it’s a African ape and human beings and modern African apes have had common ancestors, chimpanzee is more common in evolutionary terms.

40. The human species has genetic roots in:
A. America
B. Africa
C. Australia
D. Antarctica

Answer

→ Africa
This is because studies show that human and Modern African Ape shared a common ancestor millions of years ago. So, humans are believed to have evolved in Africa.

41. Which of the following gas was not present in early earth atmosphere?
A. Ammonia
B. Oxygen
C. Hydrogen sulphide
D. Methane

Answer

→ Oxygen
Due to the absence of free oxygen, the organic molecules remain unspoiled and reacted to produce new and more complex organic compounds.

42. A gradual change, over a long period, in a form of life is known as :
A. Erosion
B. Evolution
C. Revolution
D. Evaluation

Answer

→ Evolution
Evolution is a phenomenon that brings about continuous and orderly changes in nature. It is a change through time in physical or biological world.

43. Scientists believe that all life originated in:
A. The sea
B. The soil
C. The ground
D. The air

Answer

→ The sea
It is believed that life originated about 3.5bya in sea, near deep sea hydrothermal vents.

44. According to scientists, aves have evolved from:
A. Mammals
B. Amphibians
C. Reptiles
D. Arthropods

Answer

→ Reptiles
Aves have evolved from reptiles. Archaeopteryx lithographica is a connecting link between reptiles and aves. The fossil bird was of the size of crow and had both reptilian and avian characters.

45. The theory of evolution of species by natural selection was given by:
A. Mendel
B. Darwin
C. Dalton
D. Lamarck

Answer

→ Darwin
Charles Robert Darwin wrote a book ‘Origin of Species’ in which he gave The theory of Evolution of species by Natural Selection.

46. The term 'father of genetics' is used for the scientist:
A. Morgan
B. Mendel
C. Darwin
D. Marie Curie

Answer

→ Mendel
Gregor Johann Mendel is known as the father of genetics. He worked on Pea plant and discovered the fundamental laws of inheritance.

47. One of the following traits cannot be inherited. This one is:
A. Color of eyes
B. Color of skin
C. Size of body
D. Nature of hair

Answer

→ Size of body
Size of body cannot be inherited because it depends on division capability of somatic cells and physical efforts also. The rest are inherited through gametes.

48. Only one of the following characteristic of the parents can be inherited by their children. This one is:
A. Deep scar on chin
B. Snub nose
C. Technique of swimming
D. Cut nose

Answer

→ Snub nose
This is because the rest of them cannot be inherited as they are related to somatic cell characteristics and learning. Only snub nose can be inherited as its trait would be carried in the gene.

49. The organs which perform different functions but have the same basic structure are known as:
A. Homologous organs
B. Analogous organs
C. Homolytic organs
D. Analytic organs

Answer

→ Homologous organs
These organs are similar in their basic structure but they perform different functions. For example- Forelimbs of bird are used for flying, whereas forelimbs of man are used for grasping (i.e. they have same basic structure of bones but perform different functions.)

50. The organs which perform similar functions but have different basic structure are called:
A. Asymmetric organs
B. Analogous organs
C. Homologous organs
D. Homophonic organs

Answer

→ Analogous organs
These organs perform similar functions but have different basic structure. For example- Wing of an insect and wing of a bird perform the same function of uplifting the body in air but their basic structure is totally different.

51. Wing of an insect and forelimb of a bird are:
A. Analogous organs
B. Analeptic organs
C. Homologous organs
D. Homophobic organs

Answer

→ Analogous organs
Wing of an insect and forelimb of a bird help them to lift their body up in the air but their basic structure is totally different, so they are analogous organs.

52. If the fossil of an organism is found in the deeper layers of earth, then we can predict that:
A. The extinction of organism has occurred recently
B. The extinction of organism has occurred thousands of years ago
C. The fossil position in the layers of earth is not related to its time of extinction
D. Time of extinction cannot be determined.

Answer

→ The extinction of organism has occurred thousands of years ago.
Fossils are formed in sedimentary rock which is formed in layers by the deposition and pressure of sediments on top of each other thus the oldest layers are on the bottom, and the youngest layers are on the top.

53. Which of the following statement is incorrect with respect to variations?
A. All variations in a species have equal chance of survival
B. Change in genetic composition results in variations
C. Selection of variations by environmental factors forms the basis of evolutionary process
D. Variations are the minimum in asexual reproduction

Answer

→ All variations in a species have equal chances of survival.
This is incorrect because nature follows survival of the fittest. If variation in a species does not let the organism adapt to surroundings it would not survive for long whereas the species that will be able to adapt to surroundings will survive.

54. One of the following traits of the parents cannot be passed on to their future generations. This trait is:
A. Cleft chin
B. Pointed chin
C. Scarred chin
D. Broad chin

Answer

→ Scarred chin
This trait cannot be passed from parents to future offspring because chin gets scarred when the somatic cells of the chin are damaged and it is not a trait that is transferred genetically.

55. Some dinosaurs had feathers although they could not fly but birds have feathers that help them to fly. In the context of evolution, this means that:
A. Reptiles have evolved from birds
B. There is no evolutionary connection between reptiles and birds
C. Feathers are homologous structures in both the organisms
D. Birds have evolved from reptiles

Answer

→ Birds have evolved from reptiles
Reptiles had feathers but could not fly. Over time evolution kept on taking place and with evolution the body size changed and feathers got the ability to help in to flying. Reptiles kept on evolving and their evolution led to the formation of birds which could use feathers for flying. Thus birds have evolved from Reptiles.

56. Select the incorrect statement from the following:
A. Frequency of certain genes in a population changes over several generations resulting in evolution
B. Reduction in the weight of an organism due to starvation is genetically controlled
C. Low weight parents can have heavy weight progeny
D. Traits which are not inherited over generations do not cause evolution.

Answer

→ Reduction in the weight of an organism due to starvation is genetically controlled.
This statement is incorrect/false. Reduction in weight due to starvation is a result of less amount of food consumed and is not genetically controlled.

57. New species may be formed if:
(i) DNA undergoes significant changes in germ cells
(ii) Chromosome number changes in the gamete
(iii) There is no change in the genetic material
(iv) Mating does not take place
A. (i) and (ii)
B. (i) and (iii)
C. (ii), (iii) and (iv)
D. (i), (ii) and (iii)

Answer

→ New species may be formed if DNA undergoes significant changes in germ cells and Chromosome number changes in the gamete.
If DNA undergoes changes in germ cells that will cause mutations and if chromosome number changes in the gamete it will lead to lethal consequences; both of these changes will lead to formation of new species.

58. According to the evolutionary theory, formation of a new species is generally due to:
A. Sudden creation by nature
B. Accumulation of variations over several generations
C. Clones formed during asexual reproduction
D. Movement of individuals from one habitat to another

Answer

→ Accumulation of variations over several generations
Variations when accumulate will lead to natural selection and natural selection is based on survival of the fittest. So, a new species is formed when nature starts selecting species that can survive well.

59. The presence of which of the following types of organs in two animals indicates that they are not derived from a common ancestor?
A. Homologous organs
B. Excretory organs
C. Analogous organs
D. Reproductive organs

Answer

→ Analogous organs
These organs have different origins i.e. they are not derived from common ancestor, but they perform similar functions. For example- Wings of insect and bat.

60. The presence of which of the following types of organs in two organisms indicates that they are derived from the same ancestor?
A. Analogous organs
B. Respiratory organs
C. Digestive organs
D. Homologous organs

Answer

→ Homologous organs
Homologous organs have different functions but they have basic structure of bones which means they have the same ancestor. For example-forelimbs of frog and forelimbs of man. Both have a similar basic structure of bones but forelimbs or frog are used to prop up at front ends when at rest, whereas forelimbs of man are used for grasping.

61. One of the following has not been produced from wild cabbage by the process of artificial selection. This one is:
A. Kohlrabi
B. Cabbage
C. Spinach
D. Kale

Answer

→ Spinach
Kohlrabi, cabbage and kale have been produced from Wild cabbage (Brassica oleracea) by the process of artificial selection.

62. The fossil trilobite was originally:
A. An arthropod
B. An invertebrate
C. A reptile
D. Ave

Answer

→ An arthropod
Trilobite is a fossil group of marine arthropods.

63. One pair of organs in the following animals is not homologous. This is:
A. Forelimbs in humans and lizard
B. Forelimbs in lizard and frog
C. Wings in butterfly and bat
D. Wings in bat and bird

Answer

→ Wings in butterfly and bat
Wings in butterfly and bat are analogous. They have similar functions i.e. flying but they have different ancestors from which they evolved so the pair is not homologous.

64. The wings of a housefly and the wings of a sparrow are an example of:
A. Analogous organs
B. Vestigial organs
C. Respiratory organs
D. Homologous organs

Answer

→ Analogous organs
Wings of a housefly and wings of a sparrow are analogous organs since they have similar function which is flying but they have evolved independently in each lineage separately after diverging from an ancestor without wing.

Questions Based on High Order Thinking Skills (HOTS)-Pg-211

65. Some of the important fossils which have been studied are those of organisms X, Y and Z. X were marine arthropods which were common between 400 to 600 million years ago. Y were the invertebrate animals (molluscs) with a flat, coiled, spiral shell which lived in the sea about 180 million years ago. Z are the extinct carnivorous or herbivorous reptiles which appeared on the earth about 250 million years ago and became extinct about 65 million years ago. What are X, Y and Z?

Answer

→ Marine arthropods whose fossils have been studies are known as Trilobites.
Ammonites are the extinct molluscs with flat, coiled spiral shape shell millions of years ago but are now extinct.
Carnivorous animals that appeared about 250mya and disappeared 65 mya are none other than Dinosaurs, as we all know dinosaur disappeared 65mya.

So, X- Trilobites; Y- Ammonites; Z- Dinosaurs.

66. The farmers have been cultivating a food plant X for over two thousand years and have produced as many as five entirely different looking vegetables A, B, C, D and E from it.
(a) What could the plant X be?
(b) What are A, B, C, D and E?
(c) What is the process of evolution involved in this example known as?

Answer

→ (a) X- Wild Cabbage (Brassica oleracea) is made to produce 5 different varieties of vegetables by artificial selection.
(b) These 5 different looking vegetables are Cabbage, Kohlrabi, Kale, Broccoli, and Cauliflower.



67. There are five animals A, B, C, D and E. The animal A uses its modified forelimbs for flying. The animal B uses its forelimbs for running whereas the animal C uses its forelimbs for grasping. The animal D can live on land as well as in water and uses its forelimbs to prop up the front end of its body when at rest. The animal E which respires by using spiracles and tracheae uses wings for flying but its wings are analogous to the modified forelimbs of animal A.
(a) What could the animals A, B, C, D and E be?
(b) Why are the forelimbs of animals A, B, C and D called homologous organs ?
(c) What does the existence of homologous organs in animals A, B, C and D tell us about their ancestors?
(d) Why are the modified forelimbs of animal A and the wings of animal E called analogous organs?
(e) State whether animals A and E have a common ancestor or not.

Answer

→ (a)Animals A, B, C, D and E could be sparrow, Lizard, human, frog, insect.
(b) Forelimbs of Bird, lizard, human and frog are called homologous organs because their basic structure of bones is similar but they perform different functions. This means that they have had a common ancestor and with time they adapted themselves according to the requirements.
(c) The existence of homologous organs in animals A, B, C, D tell us that since they have similar basic structure of origin, they have a common ancestor.
(d) Modified forelimbs of Bird and wings of Insect are called analogous organs because they have different basic structure but they perform similar functions. Bird uses its forelimbs to fly; similarly insect uses its wings to fly. Because their basic structure of origin is different so they do not have a common ancestor.
(e) No, Animals having analogous organs do not have a common ancestor because their basic structure of origin is different.

68. X, Y, and Z are three animals. The animal X can fly but animal Y can only run on ground or walls. The forelimbs of animals X and Y have the same basic design but they are used for different purposes such as flying and running respectively. The animal Z became extinct a long time ago. The study of fossils of Z tells us that it had some features like those of X and some like those of Y. In fact, Z is said to form a connecting link in the evolutionary chain of X and Y.
(a) What could the animals X, Y and Z be?
(b) What name is given to the forelimbs like those of X and Y which have the same basic design but different functions?
(c) Name one feature in which Z resembled X.
(d) Name one feature in which Z resembled Y.
(e) Which is the correct evolutionary chain involving X, Y and Z: X  Z  Y or YZ X?

Answer

→ (a) Bird, lizard and dinosaur; Birds can fly ; Lizards can walk on walls; Dinosaurs can fly as well as walk too)
(b) Homologous organs. (Organs that have same structure but different function)
(c) Feathered Wings as in birds
(d) Tail as in reptiles
(e) YZ X?

69. A population of red beetles lives in green bushes in a garden. Once during the process of breeding, a green beetle is produced.
(a) State whether the change in color of beetle is a process of evolution or not.
(b) Can the new color of green beetle be passed on to its next generations?
(c) What will be the advantage (if any) of the green color to the beetle?
(d) State whether the production of green color involved a change in genetic material or not.

Answer

→ (a) Yes; the change in color of beetle is a process of evolution which might have occurred to adapt to certain environmental condition.
(b) Yes; the color of green beetles can be passed on to the next generation through genes.
(c) The green color will protect the beetle from predation as it will help the beetle hide in the bushes.
(d) Yes; it involved a change in genetic material because unless and until the gene responsible for color gets some changes, no new color can be produced than the original one.

70. The organs P and Q of two animals have different structures but similar functions. On the other hand, the two organs R and S of two other animals have the same basic structure but different functions.
(a) What are the organs like P and Q known as?
(b) Name the organs like P and Q. Also name the animals which have such organs.
(c) What are the organs like R and S called?
(d) Name the organs like R and S. Also name the animals which have such organs.

Answer

→ (a) These organs that have different basic structure but perform similar functions are known as analogous organs. So organs P and Q are analogous organs.
(b) Wings of a Butterfly and wings of a sparrow; wing of an insect and wing of a bird.
(c) These organs that have similar basic structure but perform different functions are known as homologous organs. So organs R and S are homologous organs
(d) Forelimbs; Forelimbs of a frog and forelimbs of human are homologous.

Heredity and Evolution - Lakhmir Singh Manjit Kaur Solutions Pg No. 191 Class 10 Biology

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Solutions of Heredity and Evolution Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 191 Class 10 Biology

Solutions of Heredity and Evolution Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 191 Class 10 Biology

Very Short Answer Type Questions-Pg-191

1. Which of the processes, sexual reproduction or asexual reproduction, brings about maximum variations in the offspring?

Answer

→ Sexual Reproduction brings about maximum variations in the offspring because it involves fusion of gametes thus causing variations whereas asexual reproduction does not involves fusion of gametes so the offspring inherits genes from one parent only and thus variation is rare.

2. Name one variation in humans connected with ears.

Answer

→ Some humans have attached earlobes while some have few earlobes which is due to variation in genes.

5. Mendel said that the characteristics or traits of organisms are carried from one generation to the next by internal factors which occur in pairs. What is the modem name for these factors?

Answer

→ These internal factors are known as genes. Genes are found in pairs on chromosomes and they carry traits from parents to the offspring.

6. Some plants occur in one of the two sizes: tall or dwarf. This characteristic is controlled by one pair of genes. Tallness is dominant to dwarfness. Choose suitable letters for this gene pair.

Answer

→ Gene pair can be represented as Tt. T-Tallness-T and Dwarfness-t.(Dominant is always represented with a capital letter and recessive with a small letter).

7. What are the chromosomes XY and XX known as?

Answer

→ These are known as the sex chromosomes. Females have XX as the set of sex chromosome whereas males have XY as the set of sex chromosome

8. Which of the two, sperm or ovum, decides the sex of the child?

Answer

→ Sperm decides the sex of the child. During fertilization if X of the sperm fertilizes with egg (having one X chromosome) a girl child is born; if Y of the sperm fertilizes with egg a boy child is born.

9. State whether the following statement is true or false:

Answer

→ The sex of an infant is not a case of inheritance of characteristics.
False, sex of an infant is case of inheritance of characteristics. Inheritance of characters determines the sex of an infant.

10. A new born child has an XY pair of chromosomes. Will it be a baby boy or a baby girl?

Answer

→ The new born child will be a baby boy. The unfertilized egg has one X chromosome; the sperm either carries a X chromosome or a Y chromosome. If X of the sperm fertilizes with the egg the child born will be female (XX), and if Y of the sperm fertilizes with the egg the child born will be male (XY). Thus the new born child with an XY pair of chromosome will be a baby boy.

11. Which of the following combinations of sex chromosomes produce a male child: XX or XY?

Answer

→ The Combination XY produces a male child. The unfertilized egg has one X chromosome. The sperm either has a X chromosome or a Y chromosome. Male child will be produced if sperm carrying Y chromosome fertilizes with the egg. Female child will be produced if sperm carrying X chromosome fertilized with the egg. Therefore, combination XY will produce a male child.

12. Name the first scientist who studied the inheritance of traits from one generation to the next.

Answer

→ Gregor Johann Mendel studied the inheritance of traits from one generation to the next. He discovered basic principles of heredity through his experiments on pea plant.

13. What type of plants were used by Mendel for conducting his experiments on inheritance?

Answer

→ Mendel used pea plant for conducting experiments on inheritance. Reasons for selecting pea plant were
a) they are easy to raise
b) give many offspring per mating
c) self-fertilization
d) have varieties in genotype and phenotype.

14. The gene for red hair is recessive to the gene for black hair. What will be the hair color of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father ?

Answer

→ Black hair color; it is because gene for black hair color is dominant so it will be expressed and since gene for red hair is repressive so it will be suppressed under the influence of black hair gene.

15. What are the four blood groups in humans?

Answer

→ The four blood groups in humans are blood group A, B, AB and O. The ABO blood group system was given by Karl Landsteiner in 1900. He identified the blood types O, A and B.

16. Name one reptile in each case where higher incubation temperature leads to the development of:
(a) Male progeny,
(b) Female progeny.

Answer

→ (a) Incubation of eggs Lizard (Agama agama) at high temperature produces male progeny.
(b)Incubation of eggs of Turtle (Chrysema Picta) at high temperature produces female progeny.

17. Fill in the following blanks with suitable words :
(a) Genes always work in ......................
(b) In pea plants, the gene for dwarfness is………………………..whereas that for tallness is………………
(c) Most people have .................earlobes but some have ..............earlobes.
(d) A human gamete contains................... chromosomes whereas a normal body cell has ................... chromosomes in it.
(e) All races of man have.............blood groups.
(f) The.................chromosomes for a ...............are XX whereas that for a ......................are XY.

Answer

→ (a) Pair
(b) Recessive; Dominant.
(c) Free; Attached.
(d) 23; 46
(e) Same
(f) Sex; Female; Male.

Short Answer Type Questions-Pg-192

18. Which of the following represent tall plants and which represent short plants (or dwarf plants)?
(a) Tt (b) tt (c) TT
Give reason for your choice (The symbols have their usual meaning).

Answer

→ Tt- represents tall plant. This is because T is dominant so it is expressed and since t is recessive, it gets suppressed. (Where T=tall plant; t= dwarf plant)
tt- represents dwarf plant. This is because both the genes for determining the height of the plant are recessive and none of the dominating genes are present.
TT- represents tall plant. This is because T is dominant gene for height and both the dominant genes are present.

19. A man having blood group 0 marries a woman having blood group B and they have a daughter. What will be the blood group of the daughter?

Answer

→ There are equal possibilities of the daughter having blood group O and B.
Blood group O will have O and O genes whereas blood group B will have B gene as dominant and O as recessive so the gene pairs that could be formed will be either O and B or O and O ; either B and O or O and O. Hence the equal possibility i.e. 50-50.

20A. Name the scientist who gave the laws of inheritance.

Answer

→ (A) Gregor Johann Mendel gave the laws of inheritance. He studied heredity on pea plants and gave three laws of inheritance. 1. Law of Dominance. 2. Law of segregation. 3. Law of independent assortment.

20B. Name an animal in which individuals can change sex. What does this indicate?

Answer

→ (B) Snail can change sex amongst its individuals. It is usually done among the endangered snail species in order to keep themselves Alive. This indicates that genes do not play a role in determining the sex of the individual.

21. Explain with an example, how genes control the characteristics (or traits).

Answer

→ Genes are the units of heredity i.e. they transfer characteristics from parents to offspring and determine the characteristics of the offspring. Example- Transfer of hair color from parents to the offspring. Let’s say that the mother has dominant genes for black hair, (BB gene constitution) and the father has recessive gene for blonde hair (bb gene constitution). When fertilization will occur the mother will transfer one B gene for black hair to the zygote and the father will transfer one b gene for blonde hair to the zygote. The resulting offspring will have Bb gene for hair where B is a dominant gene and b is a recessive gene. Since B is dominant it will be expressed and b will be suppressed, the child will have black hair.

22A. State one advantage of variation to a species.

Answer

→ (A) Variations are heritable differences within individuals of a species. Advantage- Nature always selects the fittest organism so if no variation occurred in genes there would not have been so many species of the organism. In a changing environment, variation always increases the chances of survival of a species.

22B. What are sex chromosomes? How many sex chromosomes are there? Name them.

Answer

→ (B) Sex chromosomes are a pair of chromosome that decide/determine the sex of an individual. The 23rd pair of chromosome is Allosome (or sex chromosome).
There are 2 sex chromosomes (one pair). X and Y chromosome. Y chromosome is found only in males. X chromosome is found in both male and female.

23. Explain how, sex is determined in human babies.

Answer

→ The unfertilized egg has one X chromosome. The sperm either has a X chromosome or a Y chromosome. If sperm carrying Y chromosome fertilizes with the egg, male baby will be born with the genetic constitution XY. But if sperm carrying X chromosome fertilized with the egg, female baby will be born with the genetic constitution XX.

24. What do the following symbols used in the topic on heredity represent?
(a) TT (b) tt
(c) XX (d) XY

Answer

→ (a) TT – Tall plant (T is a dominant gene).
(b)tt- dwarf plant (t is a recessive gene and there is no dominant gene to rule over it so dwarf height).
(c)XX- Female. (Female have both the sex chromosome as X X).
(d)XY- Male. (Male have One X chromosome and the other is Y chromosome as their sex chromosome).

25A. What will you get in the F1 and F2 generations in the following cross ? Pure tall pea plant x pure dwarf pea plant?

Answer

→ (A) In the F1 generation we will get all tall plants with Tt gene combination and in the F2 generation we will get 3 tall plants (TT/Tt) and one dwarf plant (tt).


25B. Is it an example of monohybrid cross or dihybrid cross?

Answer

→ (B) This is an example of a monohybrid cross because there is just one trait i.e. height whose inheritance pattern is being studied.

26. In the F2 generation of a cross, progeny having different traits are produced in the ratio 3 : 1. State whether it is a monohybrid cross or a dihybrid cross? Give one example of such a cross.

Answer

→ It is a monohybrid cross. A monohybrid cross is a cross between two individuals with two different alleles on one gene. It produces a phenotypic monohybrid ratio of 3:1 in the F2 generation. Whereas a Dihybrid cross produces a phenotypic Dihybrid ratio of 9:3:3:1 in the F2 generation.
For example- When pure tall plant (TT) are crossed with pure dwarf plants (tt), the offspring of the F1 generation is all tall plants (Tt). When these Tall plants cross bred with each other, they produce ‘TT’ ‘Tt’ ‘Tt’ ‘tt’ offspring i.e. tall : short = 3:1. The phenotypic monohybrid ratio in the F2 generation is 3:1.


27A. What is the genotype of dwarf plants which always produced dwarf offspring ?

Answer

→ (A) Dwarf-ness is denoted by letter ‘t’ . For plants that have always produced dwarf offspring, the genotype will be ‘tt’ as dwarf-ness will only be expressed when both the genes are recessive i.e. ‘tt’

27B. What is the genotype of tall plants which always produced tall offspring?

Answer

→ (B) Tallness is denoted by letter ‘T’. For plants that have always produced tall offspring, the genotype will be TT. It can also be Tt because since dominant gene T is present it will not let the recessive trait i.e. dwarf-ness express itself.

27C. What is the genotype of (i) dwarf plants, and (ii) tall plants, whose parental cross always produces tall offspring?

Answer

→ (C) (i)Genotype of dwarf plants will be ‘tt’ because dwarf-ness is a recessive trait that is expressed only when both the genes are recessive.
(ii)Genotype of tall plant will be ‘TT’ because the parental cross is producing tall offspring always.

28A. If a normal human cell has 46 chromosomes, how many chromosomes will be there in a human (i) sperm cell, and (ii) zygote?

Answer

→ (A) (i) sperm cell will have 23 chromosomes as gametes consist of half the number of chromosome of somatic cells.
(ii) Zygote will have 46 chromosomes as 23 chromosomes from the gamete of mother (egg) and 23 chromosome from the gamete of the father (sperm) will fuse to a total of 46 chromosomes.

28B. (b) What sizes of plants are produced if both parents have genes Tt?

Answer

→ (b) When both parents have same genes Tt and Tt and they are made to cross bred, we get a phenotypic ratio of 3:1 of tall: dwarf. (TT, Tt, Tt, tt)

29. In a human, how many chromosomes are present in:
(a) a brain cell ?
(b) a sperm in the testes ?
(c) an egg which has just been produced by the ovary?
(d) a skin cell ?
(e) a fertilized egg ?

Answer

→ (a) 46 (23 pairs of chromosome)
(b) 23 chromosomes (haploid)
(c) 23 chromosomes (haploid)
(d) 46 chromosomes (23 pairs of chromosome)
(e) 46 chromosomes (since it is fertilized by the sperm)

30. Gregor Mendel's first law of genetics states "Of a pair of contrasted characters, only one can be represented in a gamete by its internal 'factor'.
(a) Give the modem name for this 'factor'.
(b) State where these factors are found in gametes.

Answer

→ (a) This factor is known as Genes. They are unit of heredity transferred from parents to offspring. Each parent has a gene pair in each cell for each trait studied. One member of the gene pair segregates into a gamete, thus each gamete only carries one member of the gene pair and hence only one out of a pair of contrasted characters is represented in a gamete by its gene.
(b) These internal factors known as genes are found on chromosomes which are made of DNA and protein and found in the nucleus of the cell.

31. Does genetic combination of mother play a significant role in determining the sex of a new born baby?

Answer

→ No, the genetic constitution of mother does not play a significant role in determining the sex of baby. This is because mother has 2 X sex-chromosomes (i.e. XX) so the baby will inherit an X chromosome from the mother. It is the father whose genetic constitution plays important role. Father has XY sex chromosomes so the baby will either inherit X chromosome or Y chromosome through sperm. If the sperm carries X chromosome the baby born will be a girl (XX) and if the sperm carries Y chromosome the baby born will be a boy (XY).

32. Give the contrasting traits of the following characters in pea plant and mention which is dominant and which is recessive:
(a) Yellow seed (b) Round seed

Answer

→ (a) Green seed is the contrasting trait of yellow seed where Green is recessive and yellow is dominant.
(b) Wrinkled seed is the contrasting of round seed where Wrinkled is recessive and round is dominant.

NCERT Solutions for Class 10th: Ch 4 Le plaisir de lire French

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NCERT Solutions for Class 10th: Ch 4 Le plaisir de lire French

Page No: 34

À TOI

I. Coche la bonne réponse:

1. Ce texte est
(i) un conte.
(ii) un texte publicitaire.
(iii) un reportage.
► (iii) un reportage.

2. Ce texte s'adresse aux
(i) jeunes.
(ii) professeurs.
(iii) enfants.
► (i) jeunes.

3. Dans le texte on parle
(i) des devoirs des enfants.
(ii) des écoles.
(iii) des bibliothèques.
► (iii) des bibliothèques.

II. Complète avec des mots du texte:

1. Pour avoir une carte de lecteur, il faut une ..................... une ..................... et une ....................
2. De la bibliothèque, on peut emprunter des .............. des .................. et des ......................
3. .................................. est un roman policier français.

Answer

1. Pour avoir une carte de lecteur, il faut une carte d'identitè, une autorisation des parents et une quittance d'électricité ou de loyer.
2. De la bibliothèque, on peut emprunter des livres des CDs or DVDs et des magazines.
3. Tom Sawyer est un roman policier français.

Page No. 35

I. Remplis par un mot du texte:

1. Il a ................... à son baccalauréat.
2. Quand j'ai pris sa photo, le crocodile ..................... un lapin.
3. Il a mené une vie pleine d' ...................
4. Le serpent a attaqué le rat et .................... il l'a avalé.
5. Il ne peut plus .................... la jambe après l'accident

Answer

1. réussi
2. avalait
3. aventures
4. ensuite
5. bouger

Page No. 36

II. Trouve dans le texte la forme nominale des verbes suivants:
1. digérer
2. dessiner
3. lire

Answer

1. la digestion
2. le dessin
3. la lecture

Page No. 37

I. Conjugue les verbes au plus-que-parfait ou au passé composé:

1. Lorsque les élèves ................. (finir)leurs examens, ils ..........................(s'amuser) bien.
2. Aussitôt qu'elle ................ (rentrer)de son voyage, elle ............... (rencontrer) son directeur.
3. Quand Nicolas .................... (lire) le roman, il le .................(prêter) à son ami.
4. Dès que nous ................... (entendre)la nouvelle, nous ........................ (téléphoner) à notre professeur.
5. Quand Odette ................... (sonner) à la porte, son amie ................... déjà (partir).

Answer

1. Lorsque les élèves avaient fini leurs examens, ils se sont bien amusés bien.
2. Aussitôt qu'elle était rentrée de son voyage, elle a rencontré son directeur.
3. Quand Nicolas avait lui le roman, il le l'a prêtéà son ami.
4. Dès que nous avions entendu la nouvelle, nous avons télephoneà notre professeur.
5. Quand Odette a sonné à la porte, son amie était déja partie déjà.

Page No. 39

I. Mets en ordre:

1. C'est Perrault qui l'avait écrit.
2. Que lis-tu?
3. C'est un écrivain français du XVII siècle. Tu ne connais pas le conte Le Petit Chaperon rouge?
4. Oui, mes parents me l'avaient raconté quand j'étais petit.
5. Je suis en train de lire les contes de Perrault.
6. C'est qui, Perrault?

Answer

2. Que lis-tu?
5. Je suis en train de lire les contes de Perrault.
6. C'est qui, Perrault?
3. C'est un écrivain français du XVII siècle. Tu ne connais pas le conte Le Petit Chaperon rouge?
4. Oui, mes parents me l'avaient raconté quand j'étais petit.
1. C'est Perrault qui l'avait écrit.

II. Rétablis l'ordre des mots:

1. Un s'agit prince il d'petit ce récit dans.
2. Récit est ce par écrit St. Exupéry.
3. S'adresse seulement enfants mais aux il non adultes aux aussi.
4. Lui-même fait y a l'auteur dessins des.
5. Raconte expériences les l'auteur prince petit du

Answer

1. Il s' agit d' un prince dans ce poéme.
2. Ce récit est écrit par St. Exupéry.
3. Il s'adresse non seulement aux enfants mais aussi aux adultes.
4. L'auteur lui-même y a fait des dessins.
5. L'auteur raconte les expériences du petit prince.

III. Lis cette petite lettre et complète les phrases en mettant les verbes au plus-que- parfait:

Ma chère Livia,
Voilà deux petites cartes que j' ........................  en été. Je suis allée en France, j' .................  le beau lac d'Annecy et j' ...............  le Mont

Answer

Ma chère Livia,
Voilà deux petites cartes que j' avais achetées en été. Je suis allée en France, j' avais visité le beau lac d'Annecy et j' avais vu  le Mont

Page No. 40

IV. Tu veux emprunter des livres à la bibliothèque de la ville. Tu t'adresses à la réceptionniste. Rédige le dialogue: (environ 40 mots).

Answer

Vous: Bonjour madame! J'aimerais emprunter des livres.
Réceptionniste: Bonjour, avez-vous votre carte de bibliothèque?
Vous: Oui, je l'ai.
La réceptionniste: Ok, vous pouvez choisir les livres que vous voulez
Moi: merci! (Après vingt minutes.)
Réceptionniste: Avez-vous rapporté les livres que vous avez empruntés la dernière fois? Moi oui
Réceptionniste: Ok. Votre livre a été publié.

V. Pauline invite Denis passer quelques jours dans sa maison en Normandie. Rédige cette invitation: (environ 30 mots).

Answer

                                                                                                                                                   25 juin
Cher Denis,
Salut ! Bonnes nouvelles. J'aurai bientôt une semaine de vacances. L'école sera fermée du 2 au 9 octobre. Je décide d'aller en Normandie chez mes parents. Nous pouvons passer un bon moment ensemble. Je viendrai vous chercher à la gare le 1er juillet.
                                                                                                                                                    Amis,
                                                                                                                                                   Pauline

VI. Complète l'histoire à l'aide des mots donnés:

eau, très peu de, soif, longtemps, réfléchi, cailloux, idée, jetés, montée, envolé

Il y avait une fois un corbeau qui avait ....................... Il a cherché ................... partout mais il n'y avait pas d'......................... Finalement il a vu une maison avec un pot d'eau dans le jardin. Il y avait ........................... eau et le corbeau ne pouvait pas boire. Il a beaucoup .................................... Il a eu une bonne ........................... Il a pris des ....................... et il les a ......................... dans l'eau. L'eau est ......................... Le corbeau en a bu et il s'est .................... très content.

Answer

Il y avait une fois un corbeau qui avait soif Il a cherché longtemps partout mais il n'y avait pas d'eau Finalement il a vu une maison avec un pot d'eau dans le jardin. Il y avait très peu d' eau et le corbeau ne pouvait pas boire. Il a beaucoup réfléchi Il a eu une bonne idée Il a pris des cailloux et il les a jetés dans l'eau. L'eau est montée Le corbeau en a bu et il s'est envolé très content.

NCERT Solutions for Class 10th: Ch 5 Les médias French

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NCERT Solutions for Class 10th: Ch 5 Les médias French

Page No: 43

À TOI

I. Trouve dans le texte:

1. un mot qui indique passer d'une chaîne à l'autre.
2. une émission sur le temps.
3. une émission dramatique divisée en épisodes.
4. Un autre mot pour les infos.
5.  Un synonyme de nouvelles d'aujourd'hui.

Answer

1. Zapper
2. La météo
3. Le feuilleton
4. Le reportage
5. L'actualité

II. Dis vrai au faux:

1. TV5 est une chaîne française disponible en Inde.
► Vrai

2. Les matchs de football sont retransmis à la radio.
► Faux

3. ARTE c'est une chaîne culturelle.
► Vrai

4. Les infos: c'est la forme abrégée de «informations».
► Vrai

5. Paul veut regarder la météo.
► Vrai

Page No. 44

I. Réponds en utilisant 'y':

1. Penses-tu à tes vacances ?
Oui, ..........................

2. Va-t-il chez son cousin ?
Oui, ..........................

3. S'est-il caché derrière l'arbre ?
Non, ..........................

4. Seront-ils dans leur chambre ?
Oui, ...........................

Answer

1. Oui, j'y pense.
2. Oui, il y va.
3. Non, il ne s'y est pas caché.
4. Oui, ils y seront.

II. Réponds en utilisant 'en':

1. As- tu acheté une douzaine d'œufs?
Oui,......................................
2. Es- tu descendu du train ?
Non .....................................
3. Est- ce que Pierre sortira du bureau ?
Oui ......................................
4. Puis-je prendre trois livres ?
Oui ......................................

Answer

1. Oui, j'en ai acheté une douzaine.
2. Non, je n'en suis pas descendu.
3. Oui, Pierre en sortira.
4. Oui, tu peux en prendre trois.

III. Remplace les mots soulignés par ' y/en':

1. Mets le livre sur la table
2. Donne un bouquet de fleursà ton ami. 
3. N'entre pas dans cette salle
4. Ne mange pas de chips.

Answer

1. Mets-y le livre! 
2. Donnes-en un à ton ami! 
3. N'y entre pas! 
4. N'en mange pas!

Page No. 45

I. Complète le tableau avec les mots suivants:

auditeur - station - FM - publicité - zapper - téléfilm - téléspectateur - présentateur - interview - émission - informations - chaîne - réseau câblé

Concerne la radioConcerne la télévisionConcerne les deux












Answer

Concerne la radioConcerne la télévisionConcerne les deux
auditeurzapperpublicité
stationtéléfilmprésentateur 
FM téléspectateur interview 

émission informations 

réseau câbléchaîne 

II. Réponds:

1. Nomme quelques chaînes de télévision en France.
2. Nomme quelques chaînes de radio en France.

Answer

1. Canal+, France 2, TFI, Paris Premiére
2. Europe 1, RFI, Musique France Radio

Page No. 46

I. Choisis la bonne réponse:

1. Je me suis abonné à un lecteur / un dessin / une revue.
2. La nouvelle est dans le numéro / dans l'image / dans les journaux.
3. On achète les journaux chez le marchand de journal / à la piscine / au restaurant.
4. Un hebdomadaire paraît une fois par mois/jour/semaine.
5. Une chaîne française est TFI/le Monde/Star Plus.

Answer

1. une revue
2. dans les journaux
3. chez le marchand de journal
4. semaine
5. TEI

II. Devine ce dont on parle:

1. Un journal qu'on achète tous les jours. ........................
2. C'est là qu'on achète le journal. ........................
3. Celui qui lit un journal. ........................
4. Celui qui écrit des articles pour un journal. ........................
5. Un magazine qui paraît tous les mois. ........................

Answer

1. un quotidien
2. une librairie
3. un lecteur
4. un journaliste
5. un mensuel

Page No. 47

III. Chasse l'intrus:

1. Le Monde / Le Figaro / L'Express / La Libération.
2. Le fait divers / la météo / le quotidien / la culture.
3. TFI / France 2/ Canal + / Europe.
4. Le présentateur / le feuilleton / les actualités / la publicité.
5. Un journal / un quotidien / un hebdomadaire

Answer

1. L'Express
2. le quotidien
3. Europe
4. le présentateur
5. un journal

IV. Complète le message avec les mots suivants:

te, accompagner, urgent

Akanksha,
Je suis venue ........................ voir à 17h. Je prends un train de minuit pour aller en Suisse. C'est ...................... Demain je ne pourrai pas t' ................ au
concert.
Désolé !
Denis

Answer

Akanksha,
Je suis venue te voir à 17h. Je prends un train de minuit pour aller en Suisse. C'est urgent Demain je ne pourrai pas t' accompagner au
concert.
Désolé !
Denis

V. Mets les phrases à la forme négative:

1. Akanksha a des lettres à écrire avant de partir. ................ 
2. Kunal a une grande voiture comme son voisin....................
3. Il reste cinq mois à Paris..................
4. Je veux le voir le jour de mon anniversaire...................
5. Elle boit du café juste avant de dormir..........................

Answer

1. Akanksha n'a pas de lettres à écrire avant de partir. 
2. Kunal n'a pas de grande voiture comme son voisin. 
3. Il ne reste pas cinq mois à Paris. 
4. Je ne veux pas le voir le jour de mon anniversaire. 
5. Elle ne boit pas de café juste avant de dormir.

VI. Remplis par les pronoms: 'y'/'en': 

1.  Es - tu allé en France cet été ?
Oui, j' .................. suis allé. 

2.  Paul, a-t-il acheté des légumes au marché?
Oui, il ................ .................. a acheté. 

3. As - tu mis tes livres dans le sac ?
Non, je n' ................ ai pas mis les livres. 

4. Est - il sorti du restaurant ?
Oui, il ..................... est sorti. 

5. As-tu pensé à tes projets d'avenir ?
Non, je n' ................. ai pas pensé.

Answer

1. y 
2. y, en 
3. y 
4. en 
5. y

Our Environment - Lakhmir Singh Manjit Kaur Solutions Pg No. 226 Class 10 Biology

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Solutions of Our Environment Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 226 Class 10 Biology

Solutions of Our Environment Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 226 Class 10 Biology

Very Short Answer Type Questions-Pg-226

1. What is the functional unit of the environment comprising of the living and non-living components called?

Answer

→ The functional unit of the environment comprising of the living and non-living components is called ‘Ecosystem’.
Ecosystem includes all the living things (plants, animals) in an area interacting with each other and with their non-living environment (weather, soil, etc.) too

2. Name two natural ecosystems and two artificial Ecosystems.

Answer

→ ●Natural Ecosystem are Grassland Ecosystem and forest ecosystem; Grassland and forest are naturally created and interaction among the living and non-living things is common here. Natural ecosystem have no interference of human beings.
●Artificial ecosystem- Parks, garden, Aquariums. Artificial ecosystems are man-made ecosystem so man creates parks, gardens, aquariums where organisms interact with living and non-living components, For example- Aquarium is created by man where fishes are put inside and they are given necessary things for them to survive.

3. Which one of the following is not a terrestrial ecosystem?
Forest, Grassland, Aquarium, Desert

Answer

→ Aquarium is not a terrestrial ecosystem because terrestrial ecosystems are found only on landforms and aquarium exists in water and is an example of man-made ecosystem. Thus, forest, grassland, and desert are terrestrial ecosystems whereas aquarium is an artificial ecosystem.

4. Why are plants called producers?

Answer

→ Plants are called producers because they produce their own food through the process of photosynthesis where they utilize sunlight, carbon dioxide, water, chlorophyll to produce nutrients and release oxygen as a by-product.

5. What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants?

Answer

→ Organisms that break down the complex organic compounds present in dead animals and plants are known as Decomposers. Decomposers break down the complex organic compounds in dead animals and plants to obtain nutrients from the dead and decaying matter. For example – bacteria and fungi are decomposers.

6. What are planktons?

Answer

→ Planktons are minute organisms that live in the water but are incapable of swimming against a current. They are a source of food to aquatic organisms like fishes.

7. State whether the following statements are true or false:
(a) In biology, human beings are called producers.
(b) Secondary consumers and tertiary consumers, both are carnivores.

Answer

→ a) False. Plants are called producers because they make their own food as they have autotrophic mode of nutrition. Human beings obtain the food made by plants  and other organisms because they follow hetrotrophic mode of nutrition.
b) True. Secondary consumers eat primary consumers. They are carnivores i.e. they eat flesh and also omnivores. Tertiary consumers are at the top in a food chain and they feed on secondary consumers. Tertiary consumers are also carnivores.

8. Which category of organisms forms the starting point of a food chain?

Answer

→ Producers form the starting point of a food chain. Producers are autotrophic and they produce their own food through photosynthesis.

9. Which of the following belong to the same trophic level?
Goat; Spider; Plants; Hawk; Rat

Answer

Goat and Rat belong to the same trophic level. They belong to Herbivores as they feed on plants

10. Which of the following belong to the same trophic level?
Tree; Frog ; Snake ; Grass ; Lizard

Answer

→ Tree and Grass belong to the same trophic level. They belong to producers as they are plants i.e. they contain chlorophyll which is required to perform photosynthesis in the presence of sunlight, water, and carbon dioxide.

11. Write an aquatic food chain.

Answer

→ An aquatic food chain begins with phytoplankton like algae which are producers, these phytoplankton are eaten by zooplankton like protozoan (primary consumer). The primary consumers are eaten by secondary consumers which are small fishes in an aquatic food chain. These secondary consumers (fishes) are eaten by large fishes which are tertiary consumers. The tertiary consumers are further eaten by quaternary consumers, usually whale in an aquatic food chain. (Secondary, tertiary, and quaternary consumers are also known as carnivores).


12. Name the organisms belonging to the second and the fourth trophic levels in the food chain comprising the following:
Frogs, Plants, Snakes, Hawk, Insects.

Answer

→ Second trophich level in a food chain is Primary consumer. Primary consumers eat or feed on producers which ar eplants. Insects belong to the secondary trophich level i.e. they are primary consumers.
The fourth trophic level in a food chain is Tertiary consumers or carnivores. Snakes belong to the fourth tropic level.

13. What are the various steps of food chain called?

Answer

→ The various steps of food chain are called trophic level. A trophic level is a position that an organism occupies in a food chain.

14. Construct a food chain comprising the following: Snakes, Hawk, Rats and plant.

Answer



15. Arrange the following in a food chain: Fish, Algae, Small animals, Big Fish

Answer

→ The following is an example of aquatic food chain.


16. Which organisms belong to third and fourth trophic levels in the food chain comprising the following?
Rats, Plants, Hawk, Snakes

Answer

→ Third trophic level- Snakes (tertiary consumer) belong to the third trophic level.
Fourth tropic level- Hawk (quaternary consumer) belongs to the fourth trophic level.

17. Which one term in the following includes the others?
Air, flora, fauna, environment, water, sunlight, soil

Answer

→ Environment is the term which includes air, flora, fauna, water, sunlight and soil.
Environment is defined as the geographical surrounding in which an organism (plants, animals, human) lives. Air, flora (plants), fauna (animals) water, sunlight and soil; all are components of the environment.

18. A food chain represents a unidirectional flow of X. What is X?

Answer

→ Unidirectional flow of X represents flow of energy in a food chain. Energy is transferred via trophic levels from producers to carnivores. The energy enters the plants from sun during photosynthesis. This energy is further passed on from one organism to another in the food chain .

19. Fill in the following blanks with suitable words:
(a) Decomposer organisms are................in their action.
(b) In nature, all green plants are..................... whereas animals are consumers.
(c) A series of organisms, each of which feeds on the next organism, the beginning of which is a green plant, is called a..................
(d) The science that deals with the inter-relationships of living things with one another and their environment is called....................
(e) Plastic is a ......................material whereas paper is a..................material.

Answer

→ a) Specific;
Decomposers (like bacteria and fungi) work only on dead and decaying matter to obtain nutrients from them.
b) Producer;
Green plants have chlorophyll and they use energy from sun, water and carbon dioxide to make their own food, so they are called producers. Animals are consumers because they cannot make their own food. They either eat plants or other animals.
c) Food chain;
Food chain can be defined as a series of organisms where each organism is dependent on the next for food.
d) Ecology;
Ecology is the study of how organisms interact with each other and their environment.
e) Non-biodegradable; biodegradable.
Plastic is non-biodegradable because it is rarely consumed by bacteria so they do not decompose. Whereas, paper is biodegradable because paper is made of plant material and plant materials are biodegradable.

Short Answer Type Questions-Pg-226

20. Explain the terms 'producer' and 'consumer'. Give two examples of producers and two of consumers.

Answer

→ Producers are defined as organisms that prepare their own food using inorganic substances like water, carbon dioxide in the presence of chlorophyll and sunlight, and they release oxygen as a by-product. For example- green plants, blue algae, lichens etc. are producers , they make their own food by the process of photosynthesis.

Consumers are organisms that cannot make their own food and so they depend on producers for food. For example- Lion, Bears, Tiger are consumers.

21A. Define decomposers. Name one decomposer.

Answer

→ (A) Decomposers are organism that breakdown the organic components of dead and decaying matter (plants and animals) into simpler substances and feeds on them. Decomposers are usually microorganisms like bacteria and fungi which obtain their nutrients from dead and decaying matter.

21B. What is the role of decomposers in the ecosystem?

Answer

→ (B) Decomposers play a vital role in the ecosystem as they breakdown the organic components of dead and decaying matter into simpler substances. The organic matter is recycled in the ecosystem thus acting as cleansing agent for the environment.

22. What is meant by a primary consumer, secondary consumer and a tertiary consumer? Give one example of each.

Answer

→ ●Primary consumer- Primary consumers are living organisms that only eat plants i.e. producers. Herbivores/ plant eaters are primary consumers. For example- Goat, Rabbit.
●Secondary consumer- Secondary consumers are organisms that eat herbivores/ primary consumers for their food/ nutrient requirements. They are known as carnivores that feed on herbivores. For example- Frog, rat etc.
●Tertiary consumer- tertiary consumers are organisms that feed on secondary consumers. Basically, tertiary consumers are large carnivores which feed on small carnivores. For example- Owl, lion, etc.

23. Give an example of a four step food chain operating in grassland. Name the secondary consumer in this food chain.

Answer

→ Example of a food chain operating in grassland


24A. Define trophic level. Draw the food chain with four trophic levels.

Answer

→ (A)
Trophic level is the steps in a food chain where transfer of food in the form of energy takes place between organisms. At each step in a food chain is an organism that forms the trophic level.
A food chain consisting of four trophic levels.


24B. What will happen if we kill all the organisms in one trophic level?

Answer

→ (B)
If all the organisms in one trophic level are killed then the transfer of energy to the next trophic level will stop. Also it will cause over population at one of the trophic level whose predators will be killed. Thus, disturbing the food chain completely.

25. What is the difference between the food habits of organisms belonging to the first and the third trophic levels? Give one example each of the organisms belonging to these two trophic levels.

Answer

→ The organisms at first trophic level in a food chain are producers, always. They are autotrophs, they make their own food. For example- Plants are producers
The organisms at third trophic level in a food chain are consumers. They are carnivores at third trophic level. They feed on herbivorous animals. For example frog feeds on insects.

26. Can the organisms of any trophic level be removed without causing any damage to the ecosystem? Will the impact of removing all the organisms in a trophic level be different for different trophic levels?

Answer

→ No; If organisms from any trophic level are removed, the ecosystem may collapse because it will disturb the food chain completely. There will be no transfer of energy to the next trophic level and a population of organisms, whose predators will be removed, will increase in number; thus disturbing the entire food chain and causing a great damage to the ecosystem.
Yes the impact will be different for different trophic levels. The organisms whose predators will be removed from the trophic level will increase drastically in number. The organisms whose prey will be removed will not receive energy and nutrients and thus start to disappear.
For example, Plant—Insect—Frog—Snake.
Suppose if frogs are removed, the insects will increase in number because there predators are removed. The snakes would die of starvation as their prey i.e. frogs will be removed from the trophic level.

27. Consider the food chain:
Grass Deer Lion
What will happen if all the lions are removed from the above food chain?

Answer

→ If all the lions are removed from the given food chain, the number of deer will increase because there will be no lion to prey on them; as a result the deer population will increase which will graze on grasses. More the population of deer more will be the grazing on land. Overgrazing will lead to disappearance of vegetation and the forest will turn into a desert with no vegetation at all.

28. The number of malaria patients in a village increased tremendously when large numbers of frog were exported from the village. What could be the cause for it?

Answer

→ The cause for this is increase in number of mosquitoes in the village. When large numbers of frog were exported from the village, the population of mosquito would have increased. This is because frog is predator of mosquito i.e. they eat mosquitoes, but when there were no frogs left to eat mosquito; the mosquitos increased in number thus spreading malaria.

29. How does a biodegradable waste differ from a non-biodegradable waste? Give two examples of non �-biodegradable wastes which pollute our environment.

Answer

→ Biodegradable wastes are those that can be recycled or decomposed by bacteria; therefore do not need dumping sites, and also do not cause pollution. For example- paper, wood, vegetable peels etc. Whereas, non-biodegradable wastes are those that cannot be recycled or decomposed by bacteria (not degradable) and cause pollution in the environment. Non-biodegradable waste when dumped onto large area causes soil pollution due to the poisonous chemicals present in them. For example- plastic
For example- Plastic, DDT and polythene are three such examples of non-biodegradable waste that pollute the environment.

30. Which of the following are biodegradable and which non-biodegradable?
Glass bottle, Paper, Ball point pen refill, Hay, DDT, Wheat, Cake, Wood, Polythene bag, Jute bag, Cotton cloth, Grass, Vegetable peels.

Answer

BIO-DEGRADADABLE
NON- BIODEGRADABLE
1. Paper
1. Ball point pen refill
2. Wood
2. DDT
3. Vegetable peels
3. Polythene bag
4. Cake
4. Glass bottle
5. Wheat
6. Hay
7. Jute bag
8. Cotton cloth
9. Grass
















31A. Describe an activity to show that while paper is biodegradable but plastic (say, polythene) is non- biodegradable.

Answer

→ (A) Activity- Dig a ground to 15cms depth and bury a paper and a polythene bag into it and cover it with earth. After a month or so, remove the soil from the buried area. You’ll find that the piece of paper had reduced in size because of being eaten up by the bacteria whereas the polythene bag remained as it is. The micro-organisms or the decomposers in the soil have decomposed paper. But, because the polythene bag remained as it was, it means that micro-organisms could not decompose/degrade the polythene bag.
This activity shows that paper is biodegradables and plastic is non-biodegradable.

31B. Explain why, some materials are biodegradable but some are non-biodegradable.

Answer

→ (B) From the above activity we can say that some materials are biodegradable because they can be decomposed by micro-organisms/decomposers. Some substances are non-biodegradable because the micro-organisms/decomposers cannot break or decompose them.
Decomposers are specific in their action.

32. Write down a food chain:
(a) In the sea
(b) Which ends with human-beings
(c) With five links in it.

Answer

→ a) Food chain in the sea-

b) Food chain that ends with humans.

c) Food chain with five links in it.


33. At which trophic level a person is feeding when he is eating:
(a) Roasted chicken
(b) Bread
(c) Eggs
(d) Apple
(e) Fish

Answer

→ a) Roasted chicken- Third trophic level/Secondary consumer. Chicken is primary consumer as it eats plant. Eating them will make a person a secondary consumer which is the third trophic level.
b) Bread- Second trophic level/Primary consumer. Bread is obtained from wheat plants. Eating products from plants will make a person primary consumer which is the second trophic level.
c) Eggs- Third trophic level/Secondary consumer. Egg comes from chicken which feeds on plants. Chicken are the primary consumer and eating a substance obtained from chicken will make the person a secondary consumer which is at the third trophic level, again.
d) Apple- Second trophic level/Primary consumer. Apple is obtained from plants. Eating products from plants will make a person primary consumer which is the second trophic level.
e) Fish-Fourth trophic level/Tertiary consumer. Fish is a carnivore which feeds on flesh of other animals. So fish is a secondary consumer. Eating fish will make a person tertiary consumer which is at the fourth trophic level.

34. A student went to study a local pond. In one part of the pond she noticed tadpoles scraping at some pond weed. In another part she saw a water beetle holding a tadpole in its jaws.
(a) Construct a food chain for the pond.
(b) How many links are there in this chain?

Answer

→ a) Food chain-

b) There are three links in this food chain. Tadpoles that are primary consumers eat pond weeds. Water beetles in turn eat tadpoles.

35. Construct.
(a) a long food chain, and
(b) a short food chain, ending with man.

Answer

→ a) A long food chain ending with man

b) Short Food chain ending with man


36A. State one advantage of using jute bags over plastic bags for shopping.

Answer

→ (A) one advantage of using jute bags over plastic bags is that jute bags are biodegradable and thus do not cause pollution. Whereas, plastic bags are non-biodegradable and they cause pollution by releasing toxic chemicals when burned.

36B. Write a common food chain of a pond ecosystem having four links.

Answer

→ (B) Pond ecosystem

Algae/producer are eaten by zooplankton like protozoan which are consumed by small fishes. Small fishes are prey of large fishes or large carnivores.

37. We do not clean ponds or lakes but an aquarium needs to be cleaned periodically. Why?

Answer

→ Ponds and lakes are complete ecosystems, they have decomposers which decompose the dead bodies of plants and animals and thus keep the ponds and lakes clean automatically.
Aquarium does not have decomposers to clean the dead remains of fishes, or the aquatic organisms; so they need to be cleaned periodically in order to remove the dead matter pile up.

38. What will be the consequence of the absence of decomposers in the ecosystem?

Answer

→ If decomposers get absent from the ecosystem then the dead remains of plants and animals will not be decomposed, as a result the dead matter would pile up and the nutrients will not be returned back to the plants through soil.

39. Give two differences between food chain and food web.

Answer

→ 1) A food chain is a single path of plants and animals eating each other and transferring energy accordingly. Food web is a network of interdependent food chains.
2) A food chain shows only one string of connected plants and animals and their food habits. On the other hand, a food web shows food habit of various plants and animals in an ecosystem.

40. Write one or two words for each of the following statements/definitions:
(a) Each level of food chain where transfer of energy takes place
(b) The physical factors like temperature, rainfall, light, soil, air and water of an ecosystem
(c) Organisms which depend on the producers for food either directly or indirectly
(d) The physical and biological world where we live in
(e) Self-contained unit of living things and their non-living environment needing only sunlight for its functioning

Answer

→ a) Trophic level;
10% energy transfer takes place from one trophic level to the other
b) Abiotic components of ecosystem;
Factors like temperature, rainfall, light, soil, air and water are abiotic components of the ecosystem.
c) Consumers;
Consumers feed on producers for food.
d) Environment;
The surroundings where living beings operate i.e. the physical and biological world of living beings.
e) Ecosystem.
A community wherein organisms interact with each other and their physical environment.

Our Environment - Lakhmir Singh Manjit Kaur Solutions Pg No. 227 Class 10 Biology

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Solutions of Our Environment Lakhmir Singh Manjit Kaur LAQ, HOTS and MCQ Pg No. 227 Class 10 Biology

Solutions of Our Environment Lakhmir Singh Manjit Kaur LAQ, HOTS and MCQ Pg No. 227 Class 10 Biology

Long Answer Type Questions-Pg-227

41A. What is meant by biodegradable waste materials? Give two examples of biodegradable wastes.

Answer

→ Biodegradable waste materials are those that can be recycled or can be decomposed by bacteria and do not cause pollution. For example- Paper, wood, wool, fruits are biodegradable.

41B. Which of the following materials are non-biodegradable?
Aluminum wire, Tea leaves, Synthetic fibre, wool.

Answer

→ Non-biodegradable materials are those that cannot be degraded by bacteria. Amongst the given options, Aluminum wire and synthetic fibre are non-biodegradable.

42A. What is meant by non-biodegradable waste materials ? Give two examples of non-biodegradable wastes.

Answer

→ Non-biodegradable waste materials are those that cannot be recycled or cannot be degraded by bacteria and thus cause pollution. For example- Plastic, synthetic fibre, aluminum wire, DDT insecticide are non-biodegradable.

42B. Which of the following materials are biodegradable?
Animal bones, Iron nails, Plastic mugs, Leather belts, Silver foil.

Answer :

→ Biodegradable substances are those that can be degraded by bacteria and do not cause pollution. Amongst the following, Animal bones and leather belts are biodegradable.

43A. Define an ecosystem. Give examples of any two ecosystems.

Answer

→ Functional unit of the environment comprising of the living and non-living components where the living organisms interact amongst themselves and with the non-living components as well is known as ecosystem.
For example- A grassland ecosystem where plants, animals and micro-organisms live in an environment together and grasses are the primary form of vegetation.
A forest ecosystem is a woodland unit where plants, animals and micro-organisms function all together with the non-living components of the environment.

43B. List the biotic and abiotic components of an ecosystem.

Answer :

→ Biotic components of an ecosystem are the living components that are inter-dependent and shape the ecosystem together. For example- producers make food for consumers; consumers after death are degraded by decomposers.
Abiotic components of an ecosystem are the non-living components. For example-light, temperature, water, soil, carbon dioxide, nitrogen, etc.

44A. What is a food chain? Give one example of a simple food chain.

Answer :

→ Food chain is defined as a series/ chain of organisms wherein each organism is dependent on the other for energy (food).
Example of a simple food chain-

Zebra eats grasses and are in turn eaten by lions.

44B. What is a 'food web'? Show its formation.

Answer

→ Food Web is a network of interlocking and interdependent food chain which tells us what-eats-what in an ecological community and thus describing the relationship between species.
Formation of a food web – In the food web given below, the flow of energy is shown by the direction of arrows. There are three food chains in the given food web. The food web begins from grass which is producer, it provides food to grasshopper, mice, rabbit which are eaten by lizards, and snake. Lizards, snakes, and rabbits are eaten by hawk which is carnivore. Thus, the food web begins at producers (grass) and ends in top carnivore (hawk).


45A. What is meant by 'environment'?

Answer :

→ Environment refers to the conditions where living organisms like plants, animals, human beings lives or functions. It is the physical and biological world together.

45B. What type of substances are the major pollutants of the environment? Name two such substances.

Answer

→ Non-biodegradable substance are the major pollutants of the environment. Since they cannot be recycled, degraded by bacteria they cause pollution. Substances like plastics, synthetic fibre, and Aluminum wire are non-biodegradable.

45C. Name the organisms whose uncontrolled activities are damaging the environment.

Answer

→ Human beings are the organisms whose uncontrolled activities are damaging the environment. Human beings are destroying the environment for their needs for example deforestation which leads to destruction of natural habitat for wildlife. Human beings are polluting the environment by not adapting measures to control pollution. Use of polythene bags is one such example. Every household uses polythene bags which are discarded after use and are non-biodegradable; they pollute the environment.

45D. Explain why, it is better to use paper bags than plastic bags.

Answer :

→ It’s better to use paper bags than plastic bags because paper is recyclable whereas plastic is not. Plastic cannot be degraded and they pollute the environment; whereas paper is biodegradable and does not cause any pollution. Moreover, even if burned, paper will not cause much pollution but plastics on burning will release toxic chemicals into the environment thus polluting the environment.

Multiple Choice Questions (MCQs)-Pg-228

46. Which of the following constitutes a food chain?
A. Grass, Wheat and Mango
B. Grass, Goat and Human
C. Goat, Cow and Elephant
D. Grass, Fish and Goat

Answer

→ Grass is eaten by goat and Goat may be eaten by Human.

47. In a food chain, the initial organism is usually:
A. Photosynthetic
B. Herbivore
C. Saprophytic
D. Parasitic

Answer

→ It is the Photosynthetic organisms that produce food, for example plants, which are further eaten by consumers.

48. Which of the following represents a possible food chain found in a pond:

A. a
B. b
C. c
D. d

Answer

→ This represents a possible food chain in a pound. Green algae produce food which is consumed by mosquito larvae (primary consumers/zooplankton). Mosquito larvae are eaten by fishes that are secondary consumers.

49. Which of the following are decomposers of dead organisms?
BacteriaFungiViruses
(a) noyesyes
(b) yesnoyes
(c) yesyesno
(d) yesyesyes

A. a
B. b
C. c
D. d

Answer

→ Bacteria, Fungi are decomposers of dead organisms as they breakdown the organic matter in dead and decaying organisms and feeds on them. Whereas. Viruses are not decomposers of dead organisms.

50. Which of the following is an artificial ecosystem?
A. pond
B. crop field
C. lake
D. forest

Answer

→ Crop field is an artificial ecosystem because it is a man-made ecosystem. Man makes field to grow crops and does necessary activities that are required by crops to grow. Thus, it is an artificial ecosystem.

51. Disposable plastic plates should not be used because:
A. they are made of light-weight materials
B. they are made of toxic materials
C. they are made of biodegradable materials
D. they are made of non-biodegradable materials

Answer

→ Plastics cannot be degraded and as a result they pollute the environment and threaten health.

52. In a food chain, the third trophic level is always occupied by:
A. Carnivores
B. Herbivores
C. Decomposers
D. Producers

Answer

→ The first trophic level is occupied by producers and the second by herbivores.

53. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as:
A. Eutrophication
B. Pollution
C. Bio-magnification
D. Accumulation

Answer

→ The process of accumulation of pesticides at each trophic level increases with increase in trophic levels in a food chain. This is known as bio-magnification.

54. If a grasshopper is eaten by a frog, then the energy transfer will be from:
A. Producer to decomposer
B. Producer to primary consumer
C. Primary consumer to secondary consumer
D. Secondary consumer to tertiary consumer

Answer

→ Primary consumer to secondary consumer; Grasshopper is a primary consumer which feeds on plants. Frogs are secondary consumers which eat grasshoppers.

55. An ecosystem includes:
A. all living organisms
B. non-living objects
C. both living organisms and non-living objects
D. all living organisms and input of sun's energy

Answer

→ Both living organisms and non-living objects. An ecosystem is a function unit of environment where living organisms interact with each other and the non-living objects.

56. The decomposers in an ecosystem:
A. convert inorganic material to simpler forms
B. convert organic material to inorganic forms
C. convert inorganic material into organic compounds
D. do not break down organic compounds

Answer

→ Decomposers like bacteria and fungi breakdown the organic components present in the dead and decaying matter of plants and animals into simpler inorganic forms.

57. What will happen if deer is missing in the food chain given below?
Grass → Deer → Tiger
A. The population of tigers increases
B. The population of grass decreases
C. Tigers will start eating grass
D. The population of tigers decreases and the population of grass increases.

Answer

→ The population of tigers decreases and the population of grass increases.
This is because tigers will not have food if deer go missing and hence will starve to death on not getting food and their number would decrease. On the other hand, the population of grass will increase because there will be no deer’s to eat them.

58. Organisms which synthesize carbohydrates from inorganic compounds by using radiant energy are called:
A. decomposers
B. producers
C. herbivores
D. carnivores

Answer

→ Producers i.e. plants use inorganic components water and carbon dioxide in the presence of chlorophyll and sunlight to synthesize carbohydrates and release oxygen as a by-product.

59. Organism of a higher trophic level which feed on several types of organisms belonging to a number of lower trophic levels constitute the:
A. Ecosystem
B. Food web
C. Ecological pyramid
D. Food chain

Answer

→ A food web is a system of interlocking food chains. So, the organism of a higher trophic level that feeds on several types of organisms belonging to a number of lower trophic level will constitute the food web.

60. In the following groups of materials, which group/groups contain only non-biodegradable materials ?
(i) wood, paper, leather
(ii) polythene, detergent, PVC
(iii) plastic, detergent, grass
(iv) plastic, Bakelite, DDT
A. (iii)
B. (iv)
C. (i) and (iii)
D. (ii) and (iv)

Answer

→ Polythene, detergent, PVC, Plastic, Bakelite and DDT are non-biodegradable materials i.e. they cannot be degraded.

60. In the following groups of materials, which group/groups contain only non-biodegradable materials ?
(i) wood, paper, leather
(ii) polythene, detergent, PVC
(iii) plastic, detergent, grass
(iv) plastic, Bakelite, DDT
A. (iii)
B. (iv)
C. (i) and (iii)
D. (ii) and (iv)

Answer

→ Polythene, detergent, PVC, Plastic, Bakelite and DDT are non-biodegradable materials i.e. they cannot be degraded.

61. Which of the following statement is incorrect?
A. all green plants and blue green algae are producers
B. green plants get their food from readymade organic compounds
C. producers prepare their own food from inorganic compounds
D. plants convert solar energy into chemical energy

Answer

→ Green plants get their food from readymade organic compounds.
Green plants or producers do not get their food from readymade organic compounds. Instead they use inorganic compound water and carbon dioxide to synthesize food in the presence of chlorophyll and sunlight.

62. Which of the following group of organisms are not constituents of a food chain?
(i) Grass, lion, rabbit, wolf
(ii) Plankton, man, fish, grasshopper
(iii) Wolf, grass, snake, tiger
(iv) Frog, snake, eagle, grass, grasshopper
A. (i) and (iii)
B. (iii) and (iv)
C. (ii) and (iii)
D. (i) and (iv)

Answer

→ Plankton, man, fish, grasshopper; Wolf, grass, snake, tiger are not group of food chain. Plankton and fish belong to aquatic food chain. Similarly, Wolf does not exist in a food chain with grass snake and tiger.

63. In the figure given alongside, the various trophic levels are shown in the form of a pyramid. At which trophic level the maximum energy is available?

A. T4
B. T2
C. T1
D. T3

Answer

→ Maximum energy is available at the lowest trophic level which is T1 here. The lowest trophic level in a food chain is producers. Producers have the maximum energy that they absorb from the sun. 10% of energy that they absorb from the sun is transferred to the next trophic level and so on (10% energy rule).

64. One of the following is not a biodegradable material. This one is:
A. cotton
B. animal bones
C. aluminum foil
D. wood

Answer

→ Aluminum foil is a non-biodegradable material.
Cotton, animal bones and wood are degradable.

65. Which of the following is not a non-biodegradable material?
A. Nylon socks
B. Plastic school bag
C. Jute carry bag
D. Polyester clothes

Answer

→ Plastic school bags are non-biodegradable.
Nylon, Jute, Polyester are degradable.

66. The use of one of the following will pollute the environment. This one is:
A. paper carry bags
B. cotton cloth carry bags
C. nylon cloth carry bags
D. jute carry bags

Answer

→ Nylon is a polymer of plastic and since plastic is non-degradable and create pollution in the environment, thus nylon cloth carry bags will pollute the environment.

67. One of the following is not a consumer. This one is:
A. Giraffe
B. Antelope
C. Algae
D. Alligator

Answer

→ Algae are producer.

68. Which of the following is not a producer?
A. Grass
B. Zooplankton
C. Phytoplankton
D. Paddy

Answer

→ Zooplankton; Zooplankton is a primary consumer.
Grass, phytoplankton and paddy are producers.

69. One of the following is a micro-consumer. This one is:
A. ant
B. lice
C. fungi
D. mosquito

Answer

→ Fungi; Fungi is a micro-consumer. They feed by breaking down complex organic compounds of dead and decaying matter.

70. Which of the following act as decomposers in an ecosystem?
A. Lactobacillus bacteria
B. Cyanobacteria
C. Putrefying bacteria
D. Rhizobium bacteria

Answer

→ They recycle nitrogen from dead organisms.

71. One of the following helps in the recycling of materials in an ecosystem. This one is:
A. Autotrophs
B. Saprotrophs
C. Omnivores
D. Carnivores

Answer

→ Saprotrophs (decomposers) derives nutrition from dead and decaying organic matter and thus recycles material in an ecosystem.

72. In the food chain comprising of a snake, grass, insect, and frog, the secondary consumer is:
A. Insect
B. Snake
C. Frog
D. Grass

Answer

→ Grass is producer. Insect is primary consumer as it eats grass. Frog eats insects, so it is a secondary consumer.

73. Sahara Desert was formed over a period of time due to one of the following uncontrolled activities of man:
A. Excessive cutting down of forest plants and trees
B. Excessive killing of large herbivores
C. Excessive killing of large carnivores
D. Excessive use of poisonous chemicals called herbicides

Answer

→ Carnivores i.e. lions were captured by the Romans and no carnivores were left to eat herbivores. So herbivores increased in number and they ate up all the vegetation, turning the forest into Desert.

Questions Based on High Order Thinking Skills (HOTS)-Pg-230

74. The sea water contains water beetles, tadpole, fish and weeds.
(a) Write a food chain comprising all the given organisms.
(b) Which organisms in the food chain is
(i) Herbivore
(ii) Carnivore
(c) Which organisms are
(i) Predators
(ii) Prey
(d) Which organisms can trap solar energy to make food?
(e) Which organism is a secondary consumer?

Answer

→ a) Food Chain= Weeds-Tadpoles-Water beetles-Fish
b) i) Tadpole are herbivore since they eat weed plants.
ii) Water beetle and fish are carnivore
c) i) Predators in this food chain are water beetles and fish. Water beetle eats tadpole i.e. it preys on tadpole. Fish eats water beetles i.e. it preys on water beetles
ii) Prey in this food chain are Tadpoles and water beetle. Tadpole is eaten by water beetle and water beetles are eaten by fish.
d) Weeds can trap solar energy to make food since they are green plants and contain chlorophyll.

e) Secondary consumer here is water beetle. The primary consumer is tadpole that eats weeds. The secondary consumer is water beetle, it eats tadpoles.

75. The following is a food chain that ends with human:
Plants → bee → human
(a) Explain how plants provide food for bees.
(b) How do bees provide food for humans?
(c) How does this food chain differ from a usual food chain involving human such as: plants goat human?
(d) Do you think that the food chain given in this question can really be regarded as a food chain? Explain your answer.

Answer

→ a) Bees suck nectar from flowers of the plants. Bees collect nectar and convert it to honey.
b) Humans obtain honey from bees. The honey in bees comes from sucking nectar from flowers.
c) In a food chain comprising plant goat humans, humans directly eat goat meat. Whereas, in this food chain of plants bees and humans, humans do not directly eat bees, they eat honey obtained from bees. In this way the two food chains differ.
d) The food chain given in the question is not really a food chain because humans do not directly eat the bee as a food; they first obtain food from bees in the form of honey and then consume honey.

76. A food chain occurring in the sea which provides food for many people can be written as:
Phytoplankton → Zooplankton → X → Y
(a) Name one phytoplankton.
(b) Name two zooplanktons.
(c) What could be X?
(d) Name the organism which Y could be.
(e) Which organism in the above food chain is a
(i) Primary consumer, and
(ii) Tertiary consumer

Answer

→ a) Algae is one phytoplankton found in the sea. It is a producer and it makes its own food by photosynthesis i.e. using water, carbon dioxide in the presence of sunlight and chlorophyll.
b) Crustacea, krill, copepods, protozoa, tadpole are few examples of zooplankton in the sea.
c) X could be small fishes; fishes feed on zooplankton in aquatic food chain.
d) Y could be a carnivorous fish or it can also be a man. Both, Carnivorous fish and humans feed on small fishes.
e) i) Primary consumer in the above food chain are zooplankton as they feed on phytoplankton like algae.
ii) Tertiary consumer in the above food chain can be carnivorous fish or man as they eat small fishes i.e. secondary consumers.

77. Some hunters are roaming in the plush green forest of Africa. They spot a deer and kill it. They decide to roast the deer there and then eat it. When the hunters had just finished enjoying the feast of roasted deer, a lion attacks them. The lion kills one of the hunters and eats his flesh.
(a) Write a food chain which provides food to lion in this case.
(b) Which animal (other than deer) the lion could look for food if he did not get the hunter as prey?
(c) Which other animal in the forest could have been in place of lion?
(d) How does the above food chain differ from the food chain such as:
plants → goat → man?

a) Humans are at the end of most of the food chains in which they occur (as this picture of man taking home a fish for food shows)
b) But sometimes luck runs out and humans are forced to become food for others (as this picture of lion eating a man shows). Here the human is no longer at the end of food chain. Look at the miracle of GOD: hunter has become hunted!

Answer

→ a) Food chain
Plants → Deer → hunter (man) → Lion
b) If the lion did not get hunter as a prey, he could look for rabbits in the forest
c) There could have been tiger in place of lion, in the forest. Tiger too are flesh eating animal, they could have attacked the hunter.
d) In this food chain (plant—goat--man) man is at the end and he is eating the flesh of goat. Man is a predator here.
Whereas, in the other food chain (plants—deer—man—lion) man is not at the end of the food chain and is being eaten up by the lion. Man is a prey here.

78. What would happen to the number of rabbits and grass plants if the number of foxes:
(a) Increased
(b) Decreased

Answer

→ a) If the fox population increased, the number of rabbits will decrease because more foxes will feed on rabbits thus decreasing the population of rabbits and as a result of decrease in number of rabbits, the grass plants will increase as there will be few rabbits to feed on grass.
b) If the number of foxes decreased, the number of rabbits will increase as there will be few foxes to feed on rabbits and hence it will increase the population of rabbits. When the population of rabbits will increase there will be a decrease in population of grass plants, as more and more rabbits will eat grasses so there will be a decline in grass plants.

79. What would happen to the number of grass plants and foxes if the number of rabbits:
(a) Increased
(b) Decreased

Answer

→ a) Rabbits eat grass and if they increase in number, soon the grass population would decline because rabbits will feed on grass faster than they can regrow.
b) Fox feeds on rabbits. If the number of rabbits decreased, soon the fox population will decrease because it will not get to feed on rabbits and foxes would begin to die because of starvation. And if the rabbits will decrease, the grass plants will increase in number because there will be less population of rabbits to eat grass plant.

80A. Match the terms given in column I with the terms given in column II and column III having the same meaning:

Answer

→ (A)
i) consumer-Carnivore-3rd trophic level
ii) Primary consumer-Herbivore- 2nd trophic level
iii) Producer-Autotroph-1st trophic level
iv) Tertiary consumer-Large Carnivore-4th trophic level.

80B. Give one example of a food chain having four organisms. Below each organism write the three appropriate terms from the part (a) above which you think it represents.

Answer

→ (B) Food chain – Grass-Grasshopper-Frog-Snake.

Our Environment - Lakhmir Singh Manjit Kaur Solutions Pg No. 240 Class 10 Biology

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Solutions of Our Environment Lakhmir Singh Manjit Kaur VSAQ, LAQ and HOTS Pg No. 240 Class 10 Biology

Solutions of Our Environment Lakhmir Singh Manjit Kaur VSAQ, LAQ and HOTS Pg No. 240 Class 10 Biology

Very Short Answer Type Questions-Pg-240

1. What percentage of the solar energy is trapped and utilized by the plants?

Answer

→ 1-2% of energy is trapped and used by the plant to make food. Rest of the 99-98% of solar energy that reaches the earth is reflected from surface of leaves and is absorbed by certain molecules which convert the energy into heat.

2. What percentage of energy available at the producer level is transferred at successive trophic levels in a food chain?

Answer

→ 10% of energy is transferred from producer to the next trophic level in food chain. As little as 10 percent of energy is transferred at each trophic level. The rest is lost in metabolic processes through heat.

3. Name the process in which a harmful chemical enters the food chain and gets concentrated at each trophic level.

Answer

→ Chemicals, pesticides and heavy metals move up the food chain, get into aquatic bodies and are eaten by organisms like fishes which are in turn eaten by hawks/eagles. This process where the chemical enters the food chain and gets concentrated at each trophic level is known as Biological Magnification.

4. In a food chain consisting of grass, frog, bird and insects, where will the concentration of the harmful chemical be maximum?

Answer

→ Out of above mentioned animals, birds will have maximum concentration of harmful chemicals. Birds are tertiary consumes/ carnivores, they are at top in a food chain so due to biological magnification, the concentration of harmful chemicals will be maximum in birds.

5. If a harmful chemical enters a food chain comprising cat, mice and plants, which one of these organisms is likely to have the maximum concentration of the harmful chemical in its body?

Answer

→ Cat will have the maximum concentration of harmful chemicals in its body because mice will feed on plants and cats feed on mice. The concentration of chemicals increases with increase in each trophic level.

6. Which radiations are absorbed by ozone layer?

Answer

→ Ozone layer absorbs harmful ultraviolet radiations coming from the sun and prevent it from reaching the surface of the earth.

7. Name the group of chemical compounds which damages the ozone layer.

Answer

→ Chlorofluorocarbon damages the ozone layer by destroying the ozone molecules.

8. Name two waste materials which can be recycled.

Answer

→ Paper, plastic, cardboard, aluminum foil can be recycled in mixed recycling containers.

9. Name the process by which the volume of solid wastes can be reduced.

Answer

→ Incineration is a process by which solid waste can be reduced by burning.

10. If 5 joules of energy is available at producer level (plants), then how much energy will be transferred to the lion in the following food chain?

Answer

→ 0.05joule of energy will be passed from plant to lion because only 10% of energy is transferred at each trophic level. So Goat will get 0.5joule of energy from plants and lion will get 0.05joule of energy from goat.

11. State whether the following statement is true or false:
Only 10 per cent of the light energy given by the sun is available for transfer at each higher trophic level a food chain.

Answer

→ False; Pants absorb only 1% of sun energy. 10% of this one percent energy absorbed by the plants is transferred at each trophic level.

12. Where does all the energy in living organisms originate from?

Answer

→ Sun is the major source of energy for all living organisms. Plants absorb sun’s energy to make food through photosynthesis. All the other components of a food chain obtain energy from plants.

13. Why are there rarely more than five links (or five organisms) in a food chain?

Answer

→ There are rarely more than five organisms in a food chain because there is a decrease in energy with every transfer to next trophic level and energy availability will be so small that animals will not be able to survive with small amount of energy.

14. Name two predators of snakes in a food web operating in a forest ecosystem.

Answer

→ In a forest ecosystem, peacock and hawk feed on snake.

15. Fill in the following blanks with suitable words :
(a) Ultraviolet rays can cause skin.................
(b) Pesticides enter the food chain at the ..............level
(c) Grass → ……………………….  Human
(d) lettuce  ………………………….  Fox
(e) Plants  Antelope  ……………….

Answer

→ a) Caner;
UV rays can cause skin cancer as they damage the genetic material of the skin cells causing the cells to grow out of control.
b) Producer;
Pesticides enter the food chain at the producer level as plants are the producers which are fed with pesticides.
c) Goat (or any herbivore);
Herbivores feed on Producers; herbivores are in turn eaten by consumers.
d) Rabbit ;
Rabbits feed on Lettuce which are in turn eaten by Fox
e) Lion; Plants are eaten by Antelope and Antelope are eaten by carnivores (consumers).

Short Answer Type Questions-Pg-241

16. What is ten per cent law? Explain with an example.

Answer

→ According to this law, only 10% of energy entering into trophic level of energy will be available to be transferred to the next trophic level.
For example if 1000joule of sunlight energy falls on plants and is to be transferred to herbivore and then a carnivore.

The plants or first trophic level (producers) has only 10joule of energy because plants absorb only 1% of energy that they receive from sun and according to 10% law, only 10% of 10joule will be transferred from plants to the next higher trophic level (herbivores) which is 1joule. Now 10% of 1joule =0.1 Joule which will be transferred to next higher trophic level (carnivores). So carnivores will receive 0.1 joule of energy if 1000joule of sunlight energy falls on plants.

17. Write the full form of CFC. Give its one harmful effect.

Answer

→ CFC stands for chlorofluorocarbons
Chlorofluorocarbons released into the atmosphere gradually react with ozone gas present in ozone layer and destroys ozone layer slowly thus allowing ultraviolet radiations enter into the earth.

18. Explain how, harmful ultraviolet radiations of sunlight are prevented from reaching the earth's surface.

Answer

→ Ozone layer in the stratosphere absorbs the harmful ultra violet radiations coming from the sun and thus prevent from reaching the earth surface.

19. What are the causes of depletion of ozone layer? Which diseases are likely to be caused if the ozone layer will become thinner?

Answer

→ Chlorofluorocarbons and certain ozone depleting substances are responsible for depletion of ozone layer. If the ozone layer becomes thinner, ultraviolet radiations will penetrate through the layer and reach the surface of earth which when fall on humans will destroy the genetic material of skin cells thus causing their unlimited growth and thus resulting in skin cancer.

20. Explain how harmful chemicals enter our bodies.

Answer

→ Harmful Chemicals like pesticides are sprayed on crop plants to protect them from diseases. These sprayed pesticides are absorbed by the plants because they mix up in the soil with water. From soil and water, plants absorb these pesticides. Plants are producers, they make food. Herbivores like goat consume these plants which have pesticides in them. On consuming plants accumulated with pesticides herbivores get those harmful chemicals in them. Herbivores are further eaten by carnivores like lions. Carnivores thus receive these harmful chemicals from herbivores. Humans being omnivores (both herbivores and plant eater), when eat plants or herbivores, the harmful pesticides are transferred into their bodies. This process of accumulation of harmful chemicals through each trophic level in food chain is known as biological magnification and this is how harmful chemicals reach into the bodies of humans.

21. If we excessively use pesticides to protect the crops from diseases, then it may cause long -term damage to mankind'. Justify this statement.

Answer

→ Pesticides are used to protect the crops from diseases. In this process pesticides mix up in the soil and water which are absorbed by plants. Producers are eaten by herbivores, and herbivores are eaten by carnivores. Man occupies the topmost level in a food chain as a omnivore, it eats plants as well as herbivores. The maximum amount of pesticide are accumulated at the topmost level of a food chain (biological magnification) and since human beings occupy the topmost level, the pesticides get accumulated in humans at maximum level which causes serious health issues.

22. What is meant by biological magnification? With the help of a food chain, explain how biological magnification of harmful chemicals can occur.

Answer

→ Chemicals, pesticides and heavy metals move up the food chain, get into aquatic bodies and are eaten by organisms like fishes which are in turn eaten by hawks/eagles. This process where the chemical enters the food chain and increase in concentration with increasing trophic level is known as biological magnification.


For example in the above food chain, Grass is a producer; it grows by consuming harmful chemicals from the soil. Grass is eaten by grasshopper which is further eaten by frog. Frog is eaten by snake and peacocks feed on snake. Since peacock is at the highest trophic level it will have the maximum concentration of harmful chemicals in its body, according to bio-magnification. The chemicals enter from soil to grass and they increase in concentration with increasing trophic level.

23. What is meant by bio-concentration of pesticides? Which common pesticide has accumulated in human body in considerable amounts?

Answer

→ Bio-concentration of pesticides refers to accumulation of pesticides and harmful chemicals in organisms through food chain. Bio-concentration is also defined as increase in chemical concentration in aquatic organism more than the chemicals in water.
Dichlorodiphenyltrichloroethane (DDT) is an insecticidal pesticide that accumulates in human body through the food chain. Since human beings occupy the highest trophic level in a food chain, the pesticide concentration in humans is considerably greater than the other organisms in the food chain.

24. What is garbage? What does garbage consist of?

Answer

→ Garbage is defined as anything that cannot be re-used and is waste. It usually comprises of waste from household. Garbage consists of vegetable/fruit peels, paper, plastic, cans, used packaging material, left-over food, etc.

25. Name the various modes of waste disposal.

Answer

→ There are various modes of waste disposal. Few of them are- incineration, pyrolysis, sewerage, composting, landfill, recycling, burial, biogas plant, etc.

26. How can the wastes such as paper, plastic and metal objects be disposed of?

Answer

→ Waste paper can be recycled in industries where it is processed again to form new paper. Plastics can be discarded completely by incineration. Metals are even recycled depending on their nature i.e. ferrous or non-ferrous.

27. Give a method for the disposal of household wastes such as left-over food, fruit and vegetable peels, and leaves of potted plants.

Answer

→ The best method for disposal of left-over food, fruit, vegetable peels, leafs of potted plants is composting. Compost consists of organic matter in a composting pit which is dug deep into the ground and covered with earth to ground level. The compost acts as manure to the soil as organic nutrients will be returned back to the soil when the compost decomposes.

28. What is meant by incineration? For what purpose is it used?

Answer

→ Incineration is burning of waste materials at very high temperature, in an incinerator. Incineration is used mostly by hospitals for destruction of pathogen and sharp materials completely.

29. How are most of the solid wastes in urban areas disposed of?

Answer

→ Most of the solid waste in urban areas is disposed of by creating landfill sites. The solid waste (garbage, dump, trash etc.) is dumped into landfill sites (low line areas) and covered with earth to the ground. Waste material is disposed of by burial in this method.

30. State two advantages of using disposable paper cups over disposable plastic cups.

Answer

→ 1) Disposable paper cups are easily biodegradable. They breakdown without harming the environment and can be recycled into new paper. Whereas, disposable plastic cups are made of low grade plastics and does not decompose easily and pollute the environment.
2) Even on burning paper cups will not cause air pollution as much as will be caused by burning of plastic cups. Plastic on being burned will release toxic gases whereas paper will not.

31. What is sewage? How is sewage disposed of?

Answer

→ Sewage is defined as system of carrying waste matter such as water or human urine and faeces, through underground pipes/sewers.
Sewage can be disposed of by treating it first at the sewage treatment plant where contaminants are removed from sewage to produce environmentally safe waste which is then releases into the river.

32. Write the harmful effects of ozone depletion.

Answer

→ The harmful effects of ozone depletion are-
a) More skin cancer in humans due to ultraviolet radiations which will easily reach the skin cells through stratosphere if ozone layer depletes.
b) UV radiations would also damage parts of eyes thus causing cataracts, blindness and other diseases.
c) Immunosuppression. UV radiations could damage the immune system.

33. What would happen if the ozone layer in the atmosphere completely disappears?

Answer

→ If the ozone layer in the stratosphere disappears completely then ultraviolet radiations from the sun would easily reach the earth’s surface and damage skin cells in humans with radiations thus causing cancer. It will also lead to diseases in animals and damages in plants.

Long Answer Type Questions-Pg-241

34A. With the help of a flow diagram, describe how energy from the sun flows through various trophic levels.

Answer


The energy from sun flows from producers to herbivores to carnivores.
Producers (plants) absorb sun’s energy to make food by photosynthesis. In the presence of water, carbon dioxide and chlorophyll, plants absorb 1% of sun’s energy available to them to make food in form of carbohydrates and release oxygen as a by-product. This food in the form of chemical energy flows through the food chain.
In the next step, Plants are eaten by herbivores and according to 10% energy law only 10% of energy is transferred from plants to herbivores; the rest is lost in transfer and other activities. Herbivores utilize this energy in metabolic activities and release some of the energy in form of heat into the environment.
Further, herbivores are eaten by carnivores. 10% of energy from herbivores gets transferred to carnivores. Carnivores utilize this energy for activities like respiration etc. and release some part of the un-utilized energy into the environment.

The top Carnivores obtain energy by feeding on the flesh of small carnivores and the transfer of energy keeps on happening.

34B. Explain why, the flow of energy in the ecosystem is said to be unidirectional.

Answer

→ Energy flows from plants to herbivores, then to carnivores in a food chain. Most of the energy is utilized by the organism for its activities and un-utilized energy is dissipated in the form of heat; this energy in the form of heat cannot be returned back to plant for photosynthesis. Therefore, The flow of energy in the ecosystem is said to be unidirectional.

35A. What is ozone? How is it formed?

Answer

→ Ozone is a toxic gas formed from reaction of ultraviolet radiations with oxygen. It differs from oxygen in having three molecules (O3) instead of two.
Ozone is formed when Ultraviolet radiations act on oxygen molecules. Oxygen molecules O2 are converted to ozone O3 when Ultraviolet radiations act upon them.

35B. How does ozone layer protect us from harmful effects in the environment?

Answer

→ Ozone layer protects by blocking the harmful ultraviolet radiations coming from the sun, reaching the earth and thus protecting from ailments like skin cancer, cataract and immunosuppression which occur when ultraviolet radiations reach humans.

35C. What is UNEP? What step has been taken by UNEP in 1987 to prevent too much damage to the ozone layer?

Answer

→ UNEP stands for United Nations Environment Program.
In 1987, UNEP signed an agreement to stop the CFC production at 1986 level, amongst its member countries. Montreal Protocol was signed in September 1987 which states to reduce the consumption and production of ozone depleting substances in order to reduce their quantity in the environment thus protecting the fragile ozone layer.

36A. How is energy introduced into the ecosystem?

Answer

→ Energy is introduced into the ecosystem from sun through the process of photosynthesis. Producers make their own food which flows as energy through the entire food chain. Producers use water, carbon dioxide in the presence of sunlight and chlorophyll to make food. This process is known as photosynthesis. This food then flows as energy in the entire ecosystem.

36B. Consider the following food chains:
(i) Plants → Mice →Snakes →Hawks
(ii) Plants →Mice →Hawks
If energy available at the producer level in both the food chains is 100 J, in which case will hawks get more energy as food and by how much? Justify your answer.

Answer

→ i) Plants→Mice→Snakes→Hawks.
If 100J is available at producer level (plants); mice will receive 10% of it- 10J.
10% of energy transfer will take from mice to snakes. 10% of 10J=1J. Snake will receive 1J of energy.
10% of energy will be transferred from snake to hawks. 10% of 1J=0.1J. Hawk will receive 0.1J of energy in this food chain.


ii) Plants—Mice—Hawks.
If 100J is available at producer level (plants); mice will receive 10% of it-10J
10% of 10J energy will be transferred from mice to hawks. 10% of 10J=1J.
The Hawks will receive 1J energy in this food chain.

Therefore, hawks will get more energy in the food chain which is equal to 1J and is more than 10% than the energy it is receiving in the first food chain. This is because in the first food chain Mice were being eaten by snakes, and hawks had to eat snakes, so it received less energy. In the second food chain, hawks directly ate mice, there were no snakes to consume energy in between so hawks received more energy.

37A. Explain why, a food chain usually cannot have more than three or four steps.

Answer

→ 10% energy transfer takes place from one trophic level to the next trophic level. Producers absorb one percent of sun’s energy to make food and then transfer 10% of it to the next trophic level and so on. There cannot be more than three or four steps in food chain because after that the energy availability to the organisms will be so less that the organism will not be able to survive with that less amount of energy available to them.

37B. Calculate the amount of energy that will be available to big fish in the following food chain, if 10,000 J of energy is available to small algae from the sun:
Small algae Zooplankton Fish Big fish

Answer

→ Food chain= Small algae—Zooplankton—Fish—Big fish
The algae receive 10,000J of energy out of which it absorbs only 1% i.e. 100J. 10% of 100J i.e. 10J is transferred to zooplankton. Fish receives 10% of this 10J= 1J. Out of 1J energy available to the fish, 10% is transferred to the next trophic level i.e. big fish. 10% of 1J is 0.1J. Hence, 0.1J of energy will be available to big fish if 10,000J of energy is available to small algae from the sun.

38A. Name and state the law given by Lindeman which tells us how much energy entering a particular trophic level of organisms is available for transfer to the next higher trophic level.

Answer

→ Raymond Lindeman in 1942 gave the Ten percent law. According to this law, only 10% of the energy transfer takes place from one trophic level to the next trophic level. The remaining energy is lost during transfer or broken down in respiration.

38B. How much energy will be available to hawks in the food chain comprising hawk, snake, paddy and mice, if 10,000 J of energy is available to paddy from the sun?

Answer

→ Food chain will be = Paddy—Mice—Snake—Hawk
10,000J of energy is available to paddy from sun, out of which only 1% is absorbed, 1% of 10,000J is 100J. 100J energy is absorbed by Paddy. 10% of this 100J is transferred to mice, 10% of 100J is 10J; mice receives 10J energy. 10% of 10J i.e. 1% reaches the next trophic level i.e. snake. Snake will transfer 10% of 1J to hawks; 10% of 1J is 0.1J.
Thus, 0.1J of energy will be available to hawks in the given food chain.

Multiple Choice Questions (MCQs)-Pg-242

39. What provides the energy which then flows through a food chain?
A. Glucose
B. Oxygen
C. Respiration
D. Sunlight

Answer

→ Plants that are producers in a food chain synthesize food using water and carbon dioxide in the presence of chlorophyll and sunlight which then flows in the form of energy through the food chain.

40. Which pollutant released into the air during refrigeration and air-conditioning is the greatest contributor to the depletion of ozone layer?
A. BHC
B. DDT
C. CFC
D. UNEP

Answer

→ Chlorofluorocarbon, released from refrigerators and air-conditioners are the greatest contributor in depleting the ozone layer.

41. In the food chain given below, if the amount of energy available at fourth trophic level is 5 kJ, what was the energy available at the producer level?
GrassGrasshopper  Frog  Snake  Hawk
A. 500 kJ
B. 50 kJ
C. 5000 kJ
D. 5 kJ

Answer

→ According to the 10% energy law, 10% of energy is transferred at each trophic level. So, when 5000 kJ energy is available at producer, 10% of it will be transferred to second trophic level, i.e. 500 kJ. Now, 10% of this 500 kJ will be transferred to the third trophic level i.e. 50 kJ. 10% of 50kJ will be transferred to the fourth trophic level, i.e. 5kJ.

42. Which of the following limits the number of trophic levels in a food chain?
A. Insufficient food supply from producer level
B. Decrease in energy at higher trophic levels
C. Increase in the number of organisms at higher trophic levels
D. Accumulation of harmful chemicals at higher trophic levels

Answer

→ Since only 10% of energy is transferred at each trophic level, the higher trophic level get very low amount of energy which is not sufficient for the organisms to sustain life. So, the trophic level gets restricted to amount of energy available at which the organisms at that trophic level can sustain life.

43. What percentage of sun's energy falling on the leaves of green plants is utilized by the plants in the process of photosynthesis and stored as chemical energy of food?
A. 99 per cent
B. 10 per cent
C. 1 per cent
D. 20 per cent

Answer

→ Out of all the energy that falls on leaves of green plants, only one percent is utilized by plants to make food through photosynthesis, the rest is reflected back by the leaves.

44. The depletion of ozone layer in the upper atmosphere is mainly due to the emission of:
A. Un-burnt hydrocarbons
B. Chlorofluorocarbons
C. Greenhouse gases
D. Ultraviolet radiations

Answer

→ Chlorofluorocarbon that is emitted by refrigerators and air-conditioners are responsible for depletion of ozone layer in the stratosphere.

45. In an ecosystem, the ten per cent energy available for transfer from one trophic level to the next is in the form of:
A. Heat energy
B. Light energy
C. Chemical energy
D. Mechanical energy

Answer

→ According to 10% energy rule, 10% of total energy available at each trophic level is transferred to the next trophic level in the form of food i.e. chemical energy.

46. The flow of energy in an ecosystem is always:
A. Unidirectional
B. Bidirectional
C. Cyclic
D. Multidirectional

Answer

→ The energy enters the plants from sun, during the making of food. This energy is passed from one trophic level to another in food chain.

47. The excessive exposure of humans to ultraviolet rays results in:
(i) Damage to immune system
(ii) Damage to lungs
(iii) Skin cancer
(iv) Peptic ulcers
A. (i) and (ii)
B. (ii) and (iv)
C. (i) and (iii)
D. (iii) and (iv)

Answer

→ Damage to immune system and skin cancer
Excessive exposure of UV radiations to human skin cells results in destruction of genetic material thus leading to uncontrolled growth of cells and hence causing cancer. Exposure to UV radiations also causes immunosuppression and hence damage to immune system.

48. Which of the following gets the minimum energy through the food chain in an ecosystem?
A. Carnivore
B. Large carnivore
C. Producer
D. Herbivore

Answer

→ According to the ten percent energy rule, 10% energy is transferred at each trophic level; so the organism that is at the top in a food chain will receive the lowest amount of energy. Hence, large carnivore which will be at the top in food chain will get minimum amount of energy through the food chain.(Producer-herbivore-carnivore-large carnivore).

49. A food chain comprises of cat, seed-eating bird, plants, and dog. The organism which will have the maximum concentration of harmful pesticides coming through the food chain is most likely to be:
A. Cat
B. Plants
C. Dog
D. Seed-eating bird

Answer

→ Biological magnification is the accumulation of harmful chemicals and pesticides at trophic levels in a food chain, and it is the maximum at the topmost trophic level. In this food chain, plant-seed eating bird-cat-dog; dogs are at the top so they will have the maximum concentration of harmful pesticides.

50. An aquatic food chain comprises of the organisms like tadpoles, weeds, fish and water beetles. The organism which gets the minimum energy through this food chain is:
A. Water beetles
B. Tadpoles
C. Weeds
D. Fish

Answer

→ According to 10% energy rule, the organism at the topmost level in a food chain will receive minimum energy because of 10% energy transfer at each trophic level. So in this food chain, fish being at the topmost trophic level will get minimum amount of energy through the food chain.

51. Most of the water surface of a lake is covered with algae. This algae is part of the food chain which also includes small fish, bird, larvae and big fish. Which of the following will obtain the maximum energy?
A. Big fish
B. Bird
C. Larvae
D. Small fish

Answer

→ According to 10% energy rule, 10% of energy is transferred at each trophic level. In this food chain, larvae will have the maximum amount of energy because they are at the second trophic level in a food chain and we already know that energy decreases as it moves or flows in a food chain, so after algae, larvae will have maximum energy.

52. If the energy available at the producer level in a food chain is 150 J, how much energy will be transferred to: tertiary consumer?
A. 15 J
B. 10 J
C. 1.50 J
D. 0.15 J

Answer

→ According to ten percent energy rule- 10% of energy available at producer is transferred to primary consumer, so primary consumer receives 15J energy. 10% of 15J is transferred to secondary consumer. The secondary consumer receives 1.5J energy. The tertiary consumer will receive 10% of 1.5J i.e. 0.15J.

53. If the energy transferred to a tertiary consumer in a food chain is 10 J, how much energy was available to the primary consumer?
A. 100 J
B. 500 J
C. 1000 J
D. 5000 J

Answer

→ According to 10% energy law, 10% energy is transferred at each trophic level. So if tertiary consumer gets 10J, primary consumer would have had 1000 J of energy out of which, 10% i.e. 100J gets transferred to secondary consumer, 10% of 100J will be transferred to tertiary consumer i.e. 10J.

54. In addition to wheat plants, a crop field ecosystem has organisms such as snake, peacock, eagle and mice. If the wheat plants are sprayed with pesticides periodically, which of the following will have the minimum concentration of pesticides in the body?
A. Snake
B. Eagle
C. Mice
D. Peacock

Answer

→ The food chain will be [wheat plants-mice-snake-peacock-eagle]. Mice will have the minimum concentration of pesticides. This is because, biological magnification is the increasing concentration of pesticides and harmful chemicals in organisms at higher levels in a food chain. So, eagle will have the maximum concentration and mice will have the minimum concentration of pesticide.

55. Which of the following is the best method to dispose of biological wastes from hospitals?
A. Landfill
B. Recycling
C. Incineration
D. Composting

Answer

→ Disposal of bio-medical waste i.e. waste from hospitals is best done by incineration as it destroys pathogen and sharp materials completely.

56. In an ecosystem:
(i) The flow of energy is unidirectional
(ii) The flow of materials is unidirectional
(iii) The flow of materials is cyclic
(iv) The flow of energy is cyclic
A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (iv)
D. (i) and (iii)

Answer

→ The flow of energy is unidirectional. The flow of materials is cyclic. Energy enters a food chain through producers and transfer of energy takes place from producers to decomposers through the food chain on the basis of ten percent energy rule, and is unidirectional.
The flow of materials takes place in a cyclic manner. Materials like water, carbon dioxide and nitrogen are taken up by plants to make food. This food passes from producers to herbivores and carnivores. After the death of animals, these materials are returned back to the soil from where they were taken. The materials hence are re-used for growth of new plants. Hence, flow of nutrients is cyclic in food chain.

57. The ten per cent law is associated with.
A. Transfer of energy from various trophic levels to decomposers in a food chain
B. Transfer of ATP energy into muscular energy
C. Transfer of chemical energy from one organism to another
D. Transfer of sun's energy to the organisms called producers.

Answer

→ According to ten percent law, 10% of total energy available at a trophic level is transferred to the next trophic level. Transfer of energy begins from producers and continues up to decomposers in a food chain.

58. The harmful chemical which is accumulating in human beings through food chain is:
A. Benzene hexa-chloride
B. Dichlorodiphenyltrichloroethane
C. Chlorofluorocarbon
D. Abscisic acid

Answer

→ DDT (dichlorodiphenyltrichloroethane) is an insecticide that is used to kill insects. Plants absorb it through soil and pass it up in the food chain. Because of biological magnification, it gets accumulated in human beings and may accumulate in large amount too.

59. O2 is converted into O3 by the action of:
A. Infrared radiations
B. Ultraviolet radiations
C. Gamma radiations
D. Cosmic radiations

Answer

→ Oxygen released from the plants, floats upwards into the atmosphere and is converted into ozone by ultraviolet radiations. Formation of ozone thus blocks ultraviolet radiations from reaching the earth surface.

60. Which of the following cannot be added in a composting pit to prepare compost?
A. Sunflower plants
B. Fruit and vegetable peels
C. Flowers of plastic
D. Red worms

Answer

→ Compost consists of organic matter, and plastic is not organic in nature, moreover plastic is non-degradable. To prepare compost, organic matter is added in a composting pit.

Questions Based on High Order Thinking Skills (HOTS)-Pg-243

61. The gas A is used by most of the animals to obtain energy from food by the process of respiration. When A is acted upon by radiation X, it gets converted into another gas B which is an allotrope of A but poisonous when inhaled. B forms a kind of layer C in the upper atmosphere which absorbs radiations X coming from a source Y and prevents them from reaching the earth. Some chemicals Z released from the various devices on the earth are destroying the layer C slowly. In fact, a hole has already been formed in layer Cover the area D of the earth.
(a) What are gases?
(i) A, and
(ii) B? Write their molecular formulae.
(b) Name the layer C.
(c) What are (i) X, (ii) Y, and (iii) Z?
(d) Name the area D.
(e) Name any two human ailments which may be caused by X.

Answer

→ a) i) The gas A used by animals to obtain energy from food by respiration is Oxygen O2.
ii) The gas B is Ozone O3. Radiations X (ultraviolet) when act on oxygen, convert oxygen to ozone.
b) The layer C is Ozone layer. Gas B i.e. Ozone forms ozone layer in the stratosphere.
c) i) X- Ultraviolet radiations
ii) Y- Sun. Ultraviolet radiations come from the sun
iii) Z- Chlorofluorocarbons. CFC’s are released from refrigerator and air-conditions which are destroying the ozone layer.
d) Ozone hole has been formed over Antarctica’s upper atmosphere.
e) The radiations X i.e. ultraviolet radiations cause skin cancer, when they fall on skin; they destroy the genetic material of the cells, thus resulting in uncontrolled growth of cells. These radiations are also absorbed by the lens of the eyes which leads to formation of free radicals inside the lens that causes cataract over time. Ultraviolet radiations also cause immunosuppression.

62. The surface of water in a lake appears green due to a layer of tiny free-floating organisms X on its surface. The lake water also contains organisms like water beetle, fish and tadpole. The sun shines over the lake water and provides energy for the functioning of this lake ecosystem.
(a) What could organisms X be?
(b) Write a food chain comprising of all the four organisms mentioned.
(c) What is the general name of the food chains like the one written above?
(d) Name
(i) Secondary consumer
(ii) Producer
(iii) Tertiary consumer, and
(iv) Primary consumer in the above food chain
(e) If the tertiary consumer gets 0.2 J of energy from the secondary consumer, then how much energy was radiated by the sun to the producer?

Answer

→ a) Phytoplankton- Algae are tiny free floating organisms on surface of water.
b) Food chain= Algae- tadpole- water beetle- fishes.
c) Aquatic food chain is the name given to the above food chain because this food chain exists in aquatic bodies where algae are producers, tadpoles are primary consumers, water beetles are secondary consumers and fishes are tertiary consumers.
d) i) Water beetles- secondary consumer
ii) Algae-producers
iii) Fishes- tertiary consumer
iv) Tadpole- primary consumer
e) If the tertiary consumer gets 0.2J of energy from the secondary consumer, then the producer would have received 20000J of energy from the sun. This is because of the 10% energy law. Producer receives 20,000J energy from sun and uses 1% of it to make food. 200J of energy is available at the producer. 10% of 200J is transferred to primary consumer which is 20J. Secondary consumer will obtain 10% of 20J=2J. The tertiary consumer will at last receive 10% of 2J which is equal to 0.2J. Thus, 20,000J energy was radiated from sun to producer.

63. A forest ecosystem having a lot of green plants has some foxes, lions and rabbits in it.
(a) Write a food chain comprising all the four organisms mentioned above.
(b) Name
(i) one herbivore, and
(ii) two carnivores, in this food chain.
(c) Name the link which is a predator as well as a prey.
(d) Name
(i) second trophic level, and
(ii) third trophic level.
(e) Which link of this food chain can feed on second trophic level as well as third trophic level, independently?
(f) If the sun provides 1000 J of energy to the plants, then how much energy will be transferred to fox through the food chain.

Answer

→ a) Food Chain= Green plants- rabbits-fox-lions
b) i)Herbivore- Rabbit is a herbivore
ii) Carnivore- Fox and lion are carnivores.
c) Fox is a predator as well as a prey. It eats rabbits as well as gets eaten by lion
d) i) Second trophic level- Rabbits
ii) Third trophic level- Fox.
e) Lion can feed on rabbits (secondary trophic level) as well as Fox (third trophic level), because they are carnivores.
f) If 1000J of energy is provided by sun to plants, the plant will absorb only 1% of this energy to make food. 1% of 1000J = 10J. Further, applying the ten percent rule,
The rabbits will receive 10% of 10J i.e. 1J.
10% of 1J= 0.1 J will be passed on to the foxes,.

64. A food chain consists of fish, larvae, phytoplankton and birds. The level of pesticides in water in which the fish, larvae and phytoplankton live is quite high.
(a) In which organisms the pesticides enter from the polluted water? What is this level of organisms known as?
(b) Which organism will have the maximum amount of pesticides accumulated through the food chain? What is this process known as?
(c) Write the food chain comprising all the organisms mentioned above.
(d) Which other organism you could write in place of bird in the above food chain?

Answer

→ a) Pesticides enter the Phytoplankton from the polluted water. This level of organism is known as producers. They produce their own food through the process of photosynthesis.
b) Birds will have the maximum amount of pesticides accumulated through the food chain because they are at the top in the food chain.
The process of accumulation of substances like pesticides where they move up the food chain, enter the aquatic organisms which are in turn are eaten by birds or humans is known as biological magnification.
c) Food chain= Phytoplankton-Larvae-Fish-Birds.
d) Human being can be considered in place of birds in the above food chain since they are omnivore too like certain birds; they eat food both of plant and animal origin.

65. Every household produces a lot of material A daily. In one of the methods of disposal B, material A is burned at a very high temperature of about 1000°C in a structure called C. During this process, the organic matter present is removed as D and E whereas F is left behind (which can be dumped in a landfill site).
(a) What is material A
(b) Name the method of disposal B.
(c) What is structure C known as?
(d) What are
(i) D
(ii) E, and
(iii) F?
(e) This method is especially suitable for the disposal of materials produced by certain institution. Name such institutions.

Answer

→ a) A-Garbage; Every household produces a lot of garbage daily.
b) B-Incineration; it is a method of destroying waste material by burning at high temperature.
c) C-Incinerator; incineration is carried out in an incinerator.
d) (i) D-Carbon dioxide; CO2 is the organic matter that is removed by burning of garbage.
(ii) E- Water is left behind after burning of garbage.
(iii) F- Ash is also left behind after burning of garbage.
e) Hospitals use incineration for disposal of biomedical wastes. An efficient incinerator will destroy pathogens and sharp materials and the source materials are not found in the ash that is left behind.

NCERT Solutions for Class 10th: Ch 6 Chacun ses goûts French

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NCERT Solutions for Class 10th: Ch 6 Chacun ses goûts French

Page No: 50

À TOI

I. Dis vrai ou faux:

1. Pauline est dans le salon avec ses grands-parents.
► Faux

2. R.K. Narayan est un écrivain indien.
► Vrai
3. La grand-mère de Pauline arrose les plantes.
► Vrai

4. La grand-mère aime faire le jardinage.
► Vrai
5. Le grand-père taille les rosiers.
► Faux

II. Trouve dans le texte:

1. Un synonyme de «très connu».
2. les noms de deux fleurs.
3. la forme nominale de «lire».
4. le nom d'une bande dessinée.
5. Un autre mot pour «couper une plante»

Answer

1. célèbre
2. le rose, la tulipe
3. la lecture
4. Astérix
5. taille

Page No. 51

I. Complète avec les pronoms démonstratifs:

1. Regarde ces romans. Lesquels? ........................... de Rick Riordan ? Non, ............... de J. K. Rowling.
2. Donne-moi ton adresse et .................... de Jean.
3. Ne mange pas ...................
4. ..................... n'est pas vrai.
5. Quelle femme veut-il rencontrer ? .................... ou ................... ?

Answer

1. Regarde ces romans. Lesquels? ceux de Rick Riordan ? Non, ceux de J. K. Rowling.
2. Donne-moi ton adresse et celle de Jean.
3. Ne mange pas cela.
4. Ce n'est pas vrai.
5. Quelle femme veut-il rencontrer ? celle-ci ou celle-là ?

I. Définis-les:

1. un architecte : c'est celui qui construit des bâtiments.
2. un travailleur :
3. une secrétaire :
4. un peintre : c'est celui qui peint*.
5. un professeur :

Answer

2. c'est celui qui travaille beaucoup.
3. c'est celui qui rédige les lettres, prend des notes, etc.
5. c'est celui qui enseigne les étudiants.

II. Complète avec les pronoms démonstratifs:

À Paris, j'ai visité deux musées nationaux-le Musée du Louvre et le Musée d'Orsay ..................... est plus grand que .................. Je préfère le musée d'Orsay où se trouve beaucoup de peintures impressionnistes. Parmi ces peintures, j'aime ............... de Renoir.

Answer

À Paris, j'ai visité deux musées nationaux-le Musée du Louvre et le Musée d'Orsay Celui-ci est plus grand que celui-là Je préfère le musée d'Orsay où se trouve beaucoup de peintures impressionnistes. Parmi ces peintures, j'aime celles de Renoir.

Page No. 54

I. Complète les proverbes suivants à l'aide des mots suivants:

se ressemble, risque, un œuf, aime, consent

1. Qui ne dit mot, .................................
2. Qui ......................................., s'assemble.
3. Qui ............................... bien, châtie bien.
4. Qui ne .................................rien, n'a rien.
5. Qui vole ................................, vole un bœuf.

Answer

1. se ressemble
2. aime
3. risque
4. consent
5. un ceuf

II. Mets le dialogue dans l'ordre:

- Si on allait au musée d'Orsay?
- Denis, tu es libre dimanche ?
- Volontiers.
- Et après le musée, on peut aller manger dans un restaurant indien. Je t'invite.
- Oui, je suis libre toute la journée. Pourquoi ?
- Un repas typiquement indien.
- D'accord, avec plaisir. Et qu'est-ce que tu vas me faire goûter ?

Answer

-Denis, tu es libre dimanche? 
- Oui, je suis libre toute la journée. Pourquoi? 
- Si on allait au musée d'Orsay? 
- Volontiers. 
- Et après le musée, on peut aller manger dans un restaurant indien. Je t'invite. 
- D'accord, avec plaisir. Et qu'est-ce que tu vas me faire goûter? 
- Un repas typiquement indien.

III. Chasse le mot intrus:

1. musée - monument - hôpital - cathédrale .................................
2. peintre - médecin - sculpteur - architecte. .................................
3. goût - goutte - goûter - goûteur. .................................
4. théâtre - comédien - pièce - réalisateur. .................................
5. faire la vaisselle - faire la lessive -
faire le ménage - faire un voyage. .................................

Answer

1. hôpital
2. médecin
3. goutte
4. réalisateur
5. faire un voyage

Page No. 55

IV. Complète l'histoire:

avant, ans, en, passer, oublient, seul, cet hiver, grande, en famille

La famille McCallister veut ................... ses vacances à Paris ................... Elle quitte Chicago trois jours .................... les fêtes. Quelle horreur! Kate et Peter McCallister ...................................... leur fils Kevin, qui a neuf ................... Kevin est maintenant ..................... dans la ................. maison. Kevin est ............... désespoir. Mais c'est un brave garçon. Il se débrouille. Il fait la cuisine, il regarde la télévision. Deux voleurs entrent dans la maison. Kevin est même capable d'empêcher le vol. Le film, « Maman, j'ai raté l'avion » est une comédie à voir ...................

Answer

La famille McCallister veut passer ses vacances à Paris cet hiver Elle quitte Chicago trois jours avant les fêtes. Quelle horreur! Kate et Peter McCallister oublient leur fils Kevin, qui a neuf ans. Kevin est maintenant seul dans la grande maison. Kevin est en désespoir. Mais c'est un brave garçon. Il se débrouille. Il fait la cuisine, il regarde la télévision. Deux voleurs entrent dans la maison. Kevin est même capable d'empêcher le vol. Le film, « Maman, j'ai raté l'avion » est une comédie à voir en famille

V. Dis vrai ou faux: 

1. Le théâtre est un lieu où l'on représente une pièce (de théâtre).  ( ) 
2. Le cinéma est une salle où l'on projette un film.    ( ) 
3. Le Louvre est un palais de rois de France.   ( ) 
4. Il y a une grande pyramide devant le Louvre.    ( ) 
5. Tournesols est un tableau de Renoir.    ( )

Answer

1. Vrai
2. Vrai
3.Faux
4. Vrai
5. Faux

VI. Qu'est-ce que tu fais pour te détendre ? Réponds à l'aide des expressions suivantes: 

Expressions 
Aller au cinéma Faire la lecture Regarder un spectacle Visiter un musée Aller au théâtre Écouter la musique Faire le jardinage Jouer de la musique Faire du sport

Answer

J'aime regarder des films pendant le temps libre. J'aime aussi écouter de la musique. Je vais parfois à un spectacle, visite un zoo, un musée, etc. J'aime cuisiner de temps en temps.

NCERT Solutions for Class 10th: Bilan 2 French

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NCERT Solutions for Class 10th: Bilan 2 French

Je révise ce que j'ai appris dans cette unité: (I'm reviewing what I learned in this unit:)

I. Mets en relief les mots soulignés en utilisant- c'est ….qui / c'est..que/ce sont…qui:

1. Les enfants jouent au foot. 
2. Il est tombé malade en Angleterre
3. Nous avons commandé le gâteau au chocolat.
4. Nous irons à Londres en avion
5. Mme. Legrand a acheté les roses.

Answer

1. Ce sont les enfants qui jouent au foot. 

2. C'est en Angleterre qu'il est tombé malade. 

3. C'est le gâteau au chocolat que nous avons commandé. 

4. C'est en avion que nous irons à Londres. 
5. Ce sont les roses que Mme. Legrand a achetées.

II. Remplace les noms soulignés par 'y/en':

1. Nous avons dîné souvent dans ce restaurant. 
2. Il a acheté une douzaine de pommes 
3. M. Legrand vient de sortir du bureau. 
4. Mange de la pizza! 
5. Mets le sac sur la table!

Answer

1. Nous y avons dîné souvent. 
2. Il en a acheté une douzaine. 
3. M. Legrand vient d'en sortir. 
4. Manges-en! 
5. Mets-y le sac!

III. Connais-tu la forme nominale des verbes suivants ? Complète la grille donnée ci-dessous:

La forme verbale  La forme nominale
1.écrire
2.jouer
3.arriver
4.chanter
5.servir
6.voyager
7travailler
8.décorer
9.permettre
10.inviter

Answer

La forme verbale  La forme nominale
1.écrire L'écriture
2.jouer Le jeu
3.arriver L'arrivée
4.chanter La chanson
5.servir Le service
6.voyager Le voyage
7travailler Le travail 
8.décorer La décoration
9.permettre La permission 
10.inviter L'invitation

IV. Complète avec les pronoms démonstratifs:

1. J'ai vu la maison de Nicole et la maison d'Henri, ..................... est plus grande que .....................
2. Tu as acheté deux robes, .................. est meilleure que ...................
3. Voilà des fleurs, ..................... sont plus belles que ....................
4. Il y a beaucoup de romans dans la bibliothèque, .......................... sont plus intéressants que ....................
5. Voilà des chapeaux ............... sont bleus et ............. sont rouges.

Answer

1. celle-ci, celle-là.
2. celle-ci, celle-là
3. celles-ci, celles-là
4. ceux-ci, ceux-là
5. ceux-ci, ceux-là

V. Complète avec le futur antérieur ou le futur:

1. Dès que nous ................... (sortir) du lycée, nous ...................... (pouvoir) entrer dans un IUT. (Institut universitaire de technologie)
2. Lorsque Pierre ............... (prendre) son déjeuner, il .............. (boire) de l'eau.
3. Ils ................. (aller) au lycée, aussitôt que les élèves ............... (s'habiller) .
4. Quand mes parents .................... (recevoir) de l'argent, je paierai mes frais.
5. Je jouerai avec mes amis, dès que je ................ (terminer) mon devoir.

Answer

1. serons, sortis pourrons
2. aura pris, boira
3. iront, se seront habillés
4. auront reçu
5. aurai terminé

VI. Mets au plus-que-parfait:

1. Ils ..................... à la plage avant Jean. (aller).
2. Nous .................. (vouloir) aller au Canada, mais Isabelle était malade.
3. Tu lui .................... (donner) les billets avant de partir.
4. Elle était fatiguée parce que nous ................... tard (rentrer).
5. Quand tu as vu cette robe-là, je la ................... (choisir déjà).

Answer

1. étaient allés
2. avions voulu
3. avais donné
4. étions rentrés
5. l'avais déjà choisie

VII. Mets au temps qui convient: 

1. Dans dix minutes, les filles ................... (sortir) de la maison. 
2. Aussitôt qu'elle .................. (arriver) le bébé s'est réveillé. 
3. Hier, quand Riya ................ (lire) un roman, son frère ............. (faire) du vélo. 
4. Notre professeur .................. (arriver) , il y a cinq minutes. 
5. La semaine prochaine, il ................. (aller) regarder un spectacle.

Answer

1. vont sortir
2. était arrivée
3. lisait; faisait
4. vient d'arriver
5. ira

VIII. Complète avec des prépositions: 

1. L'hôtel qui se trouve ............... musée a beaucoup de touristes en été. 
2. ....................... la carte de lecteur, tu ne peux pas emprunter des livres à labibliothèque. 
3. Il y a une île mystérieuse .................... du lac. 
4. Il a placé sa guitare .................. le mur. 
5. L'enfant s'est caché ..................... l'arbre.

Answer

1. près du 
2. Sans 
3. au milieu 
4. contre 
5. derrière

आश्रम का अनुमानित व्यय सार NCERT Class 7th Hindi

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आश्रम का अनुमानित व्यय सार वसंत भाग - 1 (Summary of Aashram ka anumanit vyay Vasant)

यह पाठ मोहनदास करमचंद गांधी द्वारा लिखित एक लेखा-जोखा है। मोहनदास करमचंद गांधी ने दक्षिण अफ्रीका से लौटकर अहमदाबाद में एक आश्रम की स्थापना की थी। इस पाठ में उसी आश्रम के व्यय के अनुमान का विवरण दिया गया है।

आरंभ में आश्रम में रहनेवाले व्यक्तियों की संख्या 40 से 50 और दस अतिथियाँ जिनमें 3-4 परिवार सहित होंगे। आश्रम के मकान के लिए 50000 वर्ग फुट जमीन की जरूरत। आश्रम में रहनेवाले कमरों के अलावा तीन रसोईघर और तीन हजार पुस्तकों के रखने के लिए पुस्तकालय और आलमरियाँ| 

खेती के लिए 5 एकड़ जमीन और उसके साथ-साथ तीस लोगों के काम के लिए खेती, बढ़ई और मोची के औजार। इन औजारों का कुल खर्च पाँच रुपये तथा रसोई के आवश्यक सामान का खर्च 150 रुपये तथा प्रति व्यक्ति मासिक खर्च 10 रुपये तय किए गए। 

सामान लाने व मेहमान के आने-जाने के लिए बैलगाड़ी 50 व्यक्तियों का अनुमानित खाने का वार्षिक खर्च 6000 रुपये तय हुआ। आश्रम में एक वर्ष में औसत पचास लोगों का छह हज़ार रुपये खर्च आएगा। उन्होंने कहा इसके लिए अहमदाबाद को ऊपर का खर्च उठाना चाहिए। उन्होंने कहा यदि ऐसा करने हेतु अहमदाबाद तैयार नहीं तो वे ऊपर के खर्च का इंतजाम कर सकते हैं। इस लेखा-जोखा में गांधी जी ने लोहार, राजमिस्त्री और शिक्षण संबंधी खर्च शामिल नहीं किया था।

कठिन शब्दों के अर्थ -

• आरंभ - शुरूआत
• संभावना - उम्मीद
• औसतन - लगभग
• अतिथि - मेहमान
• व्यवस्था - इंतजाम
• लायक - योग्य
• बढ़ईगीरी - लकड़ी के काम करने की कला
• मासिक - महीने का
• मालूम - ज्ञात 
•मदों में - वस्तुओं पर
• जुटाना - प्रबंध करना


विप्लव-गायन सार NCERT Class 7th Hindi

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विप्लव-गायन सार वसंत भाग - 1 (Summary of Viplav Gayan Vasant)

यह कविता एक क्रांति गीत है जिसके द्वारा कवि से जीवन में परिवर्तन लाना चाहते हैं। उन्हें लगता है कि संघर्ष करके समाज बदला जा सकता है। इसमें जड़ता के विरुद्ध विकास और गतिशीलता की बात कही गई है।

कवि अपने साथी कविओं को संबोधित करते हुए कहते हैं कि तुम अपनी परिवर्तन संबंधी भावनाओं से कोई ऐसी जोशीली तान सुनाओ, जिसे सुनकर सारे संसार में उथल-पुथल मच जाए, कुछ परिवर्तन आए। कविता को सुनकर आँधी का एक झोंका इधर से आए और दूसरा झोंका उधर से आए जिससे जीवन में बदलाव आए| कवि कहता है कि मेरी वीणा पर अब आग की चिंगारियाँ आ बैठी हैं। अब यह मधुर स्वर उत्पन्न नहीं करेगी। वीणा से मधुर तान उत्पन्न करने वाली मिज़राबें टूट चुकी हैं और वीणा बजाने वाली मेरी दोनों अंगुलियाँ अकड़ गई हैं। अब ये परिवर्तन लाना चाहती हैं।

कवि कहते हैं कि मेरे स्वर को प्रकट करने वाला गला जोश की अधिकता से रुक गया। इससे निकलने वाला विनाश का गीत रुक गया है। परन्तु अब जो परिवर्तन आएगा वह रुक नहीं पाएगा क्योंकि वह आक्रोश हमारे अंतरमन से उठा है जो इन परंपराओं, रूढ़ियों को पूरी तरह से समाप्त कर देगा। मेरे मन के अंदर से उत्पन्न क्रोध भरी तान से युक्त गीत सामान्य गीत नहीं है। यह तान विकास और गतिशीलता की राह में आने वाले सभी रुकावटों को जला नष्ट कर देगा|

कवि कहते हैं कि कि उसकी वाणी के कण-कण में जोश का स्वर भरा हुआ है। उसके शरीर का एक-एक रोम परिवर्तन के स्वर दे रहा है। उसकी ध्वनि से बदलाव की तान ही उत्पन्न होती रहती है। जैसे ज़हर कालकूट को धारण करने वाले नाग के सिर पर चिंतामणि शोभा देती है वैसे ही परिवर्तन लाने वाले का जोश मुझ में शोभा दे रहा है। मैंने जीवन के सभी रहस्यों को समझ लिया है और यही भी समझ चुका हूँ कि समाज में परिवर्तन कैसे लाया जा सकता है। मैंने मृत्यु और विनाश की भृकुटियों में छिपे हुए पोषक सूत्रों को अच्छी तरह से समझ लिया है। मुझे पता है कि विचारों के परिवर्तन से ही महानाश होगा और उसके बाद ही समाज का नवनिर्माण संभव होगा।

कठिन शब्दों के अर्थ -

• हिलोर - लहर
• मिज़राब - वीणा या सितार को बजाने के लिए अंगुली पर लगाया जाने वाला तार
• आन - आकर
• कंठ - गला
• महानाश – पूर्ण विनाश
• मारक गीत - विनाश का गीत
• क्षण - पल
• दग्ध - जल उठना
• ज्वलंत - जला देने वाले
• क्रुद्ध - क्रोध से भरी
• अंतरतर - हृदय के भीतर से
• व्याप्त - विद्यमान
• कालकूट – भयंकरतम जहर
• फणि - नाग
• राज़ – रहस्य
• भ्रू - भृकुटियाँ
• पोषक सूत्र - पालन करने वाले आधार
• परख - जाँच।

Control and Coordination - Lakhmir Singh Manjit Kaur Solutions Pg No. 92 Class 10 Biology

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Solutions of Control and Coordination Lakhmir Singh Manjit Kaur VSAQ, SAQ and LAQ Pg No. 92 Class 10 Biology

Solutions of Control and Coordination Lakhmir Singh Manjit Kaur VSAQ, SAQ and LAQ Pg No. 92 Class 10 Biology

Very Short Answer Type Questions-Pg-92

1. What is the general name of chemical substances which bring about control and coordination in plants?

Answer

→ Phytohormones or plant hormones are the organic substances produced naturally in plants which control growth and other physiological activities at a site away from their synthesis.

2. Which plant hormone is responsible for the wilting and falling of leaves?

Answer

→ Abscisic acid, produced in the roots and terminal buds of the plant, is involved in many developmental plant processes, including leaf abscission, responding to environmental stress, and inhibiting fruit ripening.

3. Which plant hormone makes a stem (or shoot) bend towards light?

Answer

→ Auxin, a phytohormone produced in the stem and bud tips, promotes cell elongation. Auxins promote cell stem elongation and inhibit growth of lateral buds. They promote bending of stems or shoot towards light (also known as phototropism).

4. Where is the auxin hormone made in a plant stem?

Answer

→ Auxin phytohormone is produced in the stem, buds, and root tips.

5. What is the scientific name of sensitive plant?

Answer

→ Touch me not (also known is Chui-mui) is a touch sensitive plant. The scientific name of this plant is Mimosa pudica.

6. Name one plant hormone that promotes growth and another plant hormone which inhibits growth.

Answer

Gibberellins are growth hormones that stimulate cell elongation and cause plants to grow taller.
Abscisic acid involves in many developmental plant processes, including leaf abscission, inhibiting plant growth and fruit ripening.

7. Name one example of the movement of a plant part which is very quick and can be observed easily.

Answer

→ When we touch the leaves of Mimosa pudica (touch me not) then they get folded. It is a rapid process.

8. Name the type of chemical substances that control the growth in plants.

Answer

→ Phytohormones or plant hormones are the organic substances produced naturally in plants which control growth and other physiological activities.

9. What is the stimulus in:
(a) phototropism?
(b) geotropism?
(c) chemotropism?
(d) hydrotropism?
(e) thigmotropism?

Answer

→ (a) Light is the stimulus in phototropism.
(b) Gravity is the stimulus in geotropism.
(c) Chemical is the stimulus in chemotropism.
(d) Water is the stimulus in hydrotropism.
(e) Touch is the stimulus in thigmotropism.

10. Give the scientific terms used to represent the following:
(a) Bending of a shoot towards light.
(b) Growing of roots towards the earth.
(c) Growth of a pollen tube towards ovule.
(d) Bending of roots towards water.
(e) Winding of tendril around a support.

Answer

→ (a) The process of bending of a shoot towards light is known as phototropism.
(b) The process of growing of roots towards the earth is known as geotropism.
(c) The process of growth of a pollen tube towards ovule is known as chemotropism.
(d) The process of bending of roots towards water is known as hydrotropism.
(e) The process of winding of tendril around a support is known as thigmotropism.

11. Give one example of the movement of a plant part which is caused by the loss of water (or migration of water).

Answer

→ When we touch the leaves of a sensitive plant like touch-me not (chui-mui) then they get folded up. It shows an example of the movement of leaves which is caused by the loss of water.

12. Give one example each of a plant part:
(a) which is positively hydrotropic as well as positively geotropic.
(b) which is positively phototropic but negatively geotropic.

Answer

→ (a) Root of a plant bends towards the water in soil hence shows positive hydrotropic with positive geotropic.
(b) Stem of a plant bend towards the light above the soil hence shows positive phototropic but negative geotropic.

13. Which of the following is a growth movement and which is not?
(a) folding up of leaves of sensitive plant on touching with hand.
(b) folding up of petals of dandelion flower when light fades.

Answer

→ (a) Folding up of leaves of sensitive plant on touching with hand is not a growth movement.
(b) Folding up of petals of dandelion flower when light fades is a growth movement.

14. Name the plant part:
(a) which bends in the direction of gravity but away from light
(b) which bends towards light but away from the force of gravity

Answer

→ (a) Root of a plant bends in the direction of gravity but away from light.
(b) Shoot or stem of a plant bends towards light but away from the force of gravity.

15. To which directional stimuli do:
(a) roots respond?
(b) shoots respond?

Answer

→ (a) Roots respond to light, gravity and water stimuli.
(b) Roots respond to light and gravity.

16. Fill in the following blanks:
(a) A plant's response to light is called………………
(b) A plant's response to gravity is called………………
(c) Plant shoot grows upward in response to………………
(d) Plant roots grow downward in response to………………
(e) Tendrils wind around a support in response to ………………
(j) Plant roots grow towards ………. and in the direction of force of………………
(g) A root of a plant grows downward. This is known as………………
(h) ……..is the hormone that causes phototropism in plants
(i) The response of leaves to the sunlight is called...............

Answer

→ (a) A plant's response to light is called phototropism.
(b) A plant's response to gravity is called geotropism.
(c) Plant shoot grows upward in response to sunlight.
(d) Plant roots grow downward in response to gravity.
(e) Tendrils wind around a support in response to touch.
(j) Plant roots grow towards water and in the direction of force of gravity.
(g) A root of a plant grows downward. This is known as positive geotropism.
(h) Auxin is the hormone that causes phototropism in plants.
(i) The response of leaves to the sunlight is called phototropism.

Short Answer Type Questions-Pg-93

17. Plant parts show two types of movements, one dependent on growth and the other independent of growth.
Give one example of the movement in plant parts:
(a) which depends on growth
(b) which does not depend on growth

Answer

→ (a) Phototropism is the growth of plant parts in the direction of its light source. The bending of stem or shoot towards light shows this process.
(b) Touch me not (also known is Chui-mui) is a touch sensitive plant. When we touch the leaves of this plant then they get folded.

18. What is a plant hormone? Name four plant hormones. State one function of each. (CBSE 2015)

Answer

→ Plant hormones (also known as phytohormones) are chemicals that regulate plant growth.
4 Plant hormones:
(a) Auxins: Influence cell enlargement, bud formation and root initiation. Also promotes apical dominance.
(b) Cytokinins: Influence cell division and shoot formation.
(c) Gibberellins: Stimulate cell elongation and initiate mobilization of storage materials in seeds during germination.
(d) Ethylene: Stimulates the ripening of fruit and initiates abscission of fruits and leaves.

19A. What does a root do in response to gravity? What is this phenomenon known as?

Answer

→ Positive geotropism is the process in which the roots of plants bend downwards in the direction of gravity.

19B. What does a stem (or shoot) do in response to light? What is this phenomenon known as?

Answer

→ Positive phototropism is the process in which stem or shoot of plants bends towards the light.

20A. What does a stem (or shoot) do in response to gravity? What is this phenomenon known as?

Answer

→ Negative geotropism is the process in which stem or shoot of plants grows upward against the direction of gravity.
(b) Negative phototropism is the process in which roots of plants bend away from light.

20B. What does a root do in response to light? What is this phenomenon known as?

Answer

→ Negative phototropism is the process in which roots of plants bend away from light.

21A. What does a Mimosa pudica plant do in response to touch? What is this phenomenon known as?

Answer

→ When we touch the leaves of Mimosa pudica (also known as touch-me not or chui-mui plant), they get folded up. This phenomenon of folding up of leaves is known as thigmonasty.

21B. What happens to the dandelion flower (i) during daytime and (ii) at night? What is this phenomenon known as?

Answer

→ (i) In the morning, a dandelion flower opens up in bright light. This phenomenon is known is positive photonasty.
(ii) A dandelion flower closes at night. This phenomenon is known as negative photonasty.

22A. What does a plant root do in response to water? What is this phenomenon known as?

Answer

→ The roots of a plant grow towards the water. This phenomenon is known as hydrotropism.

22B. What happens to the moonflower (i) during daytime, and (ii) at night? What is this phenomenon known as?

Answer

→ (i) The petals of moon flower get closed during the daytime because of bright light.
(ii) The petals of moon flower get opened at night because of dark. This phenomenon is known as photonasty.

23. What is a tendril? Name the two types of tendrils. What does a tendril do in response to the touch of a support? What is this phenomenon known as?

Answer

→ A tendril is a specialized leaf, petiole or stem with a threadlike shape. It is used by climbing plants for support and attachment. The tendrils grow towards the things they happen to touch and the phenomenon is known as thigmotropism.

24. Name the five types of tropisms. How are tropic movements helpful to plants? Explain with an example.

Answer

→ The five types of tropisms are:
(a) Phototropism
(b) Chemotropism
(c) Geotropism
(d) Thigmotropism
(e) Hydrotropism
The different types of tropic movements help the plant to grow and survive. Roots grow in soil towards gravity show the geotropism.

25. Define chemotropism. Give one example of chemotropism. State whether this example is of positive chemotropism or negative chemotropism.

Answer

→ Due to chemical stimulus, the growth of a plant part is known as chemotropism. For example, a sugary substance can induce to the growth of pollen tube towards the ovule. Here, sugary substance works as a stimulus and this process represents the positive chemotropism.

26. Distinguish between tropic movements and nastic movements in plants. Give examples to illustrate your answer.

Answer

→ Tropic movements are very slow and always in the direction of stimulus. All parts of a plant (roots, stem and leaves etc.) exhibit these movements. Movement of shoot towards the light and not towards gravity is an example of this kind of movement.
Nastic movements are rapid and neither away nor towards the stimulus. Leaves and petals of flower exhibit these movements. The bending and drooping of leaves in 'Touch-me-not' plant is an example of this kind of movement.

27A. What is meant by nastic movements in plants? Give one example of nastic movements in plants.

Answer

→ Nastic movement is the movement of a plant part in response to an external stimulus. In this type of movement, the direction of response is not determined by the direction of stimulus. Leaves and petals of flower exhibit these movements. The bending and drooping of leaves in 'Touch-me-not' plant is an example of this kind of movement.

27B. What is the difference between photonasty and thigmonasty?

Answer

→ Photonasty: It is the non-directional movement of a plant part (e.g. petals of flowers) in response to light. The opening and closing of petals of dandelion flowers in response to light intensity is an example of this process.
Thigmonasty: It is the non-directional movement of a plant part in response to the touch. The folding up of Mimosa pudica leaves when touching is an example of this process.

28. A potted plant is kept horizontally for a considerable time. The three positions of the parts A and B of the potted plant are shown in the following figures:
(a) Which figure shows the correct position taken by the parts A and B of the plant?
(b) What type of phenomenon is exhibited by the figure chosen in (a) above?

Answer

→ (a) Figure (ii) shows the correct position taken by the parts A and B of the plant. As the aerial parts of the plants show positive phototropism while roots show positive geotropism.
(b) Geotropism is exhibited by the figure chosen in (A) above.

29. Name the plant hormones which are responsible for the following effects:
(a) falling of leaves
(b) opening of stomata
(c) bending of stem towards light
(d) closing of stomata

Answer

→ (a) Abscisic acid is responsible for abscission of falling of leaves.
(b) Cytokinin is responsible for opening of stomata.
(c) Auxin is responsible for bending of stem towards light.
(d) Abscisic acid is responsible for closing of stomata.

30. Name the plant organs which are:
(a) positively phototropic
(b) positively geotropic
(c) negatively geotropic 
(d) positively hydrotropic

Answer

→ (a) Stem or shoot is positive phototropic (bends towards the light).
(b) Roots are positive geotropic (grow in the soil in the direction of gravity).
(c) Stem or shoot is negative geotropic (grows above the soil against the gravity).
(d) Root are positive hydrotropic (grow in the soil for water).

31. Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism?

Answer

→ When we touch the leaves of a sensitive plant (like Mimosa pudica), they get folded. It is not a case of tropism because there is no dependency of direction of leaves movement on the direction of stimulus (touch).

32. Why is the closing of a dandelion flower at dusk (when it gets dark) not a tropism?

Answer

→ The closing of a dandelion flower at dusk (when it gets dark) is not an example of a tropism because there is no dependency of the direction of movement of petals of dandelion flower on the direction of stimulus (light).

Long Answer Type Questions-Pg-94

33A. What is meant by ‘tropisms’ (or tropic movements)? Explain with an example.

Answer

→ Tropism is the turning or bending movement of a plant in a particular direction in response to an external stimulus such as gravity or light.
Example – The process that represents the bending of plant stem towards light is known as positive phototropism.

33B. What are the different types of tropisms? Define each type of tropism. Write the name of stimulus in each case.

Answer

→ Different types of tropisms are as follows:
(i) Phototropism – It is the movement of a plant part towards light. The light is the stimulus in this process.
(ii) Geotropism – It is the movement of a plant part towards gravity. The gravity is the stimulus in this process.
(iii) Chemotropism – It is the movement of a plant part in response to a chemical. A chemical is the stimulus in this process.
(iv) Hydrotropism – It is the movement of a plant part in response to water. The water is the stimulus in this process.
(v) Thigmotropism – It is the movement of a plant part in response to touch. Touch is the stimulus in this process.

33C. How do tropisms differ from nasties (or nastic movements)?

Answer

→ Tropisms: These kinds of movements are very slow and always in the direction of stimulus. All parts of a plant (roots, stem and leaves etc.) exhibit these movements.
Nasties: These kinds of movements are rapid and neither away nor towards the stimulus. Leaves and petals of flower exhibit these movements.

34A. Define phototropism. Give one example of phototropism.

Answer

→ Phototropism is the movement of a plant part in response to a stimulus (light).

34B. How does phototropism occur in a plant stem (or shoot)? Explain with the help of labelled diagrams.

Answer

→ Phototropism in a plant stem or shoot. The bending of a plant stem towards light represents the phototropism process. Due to the action of auxin, a growth hormone, the plants stem bends towards the light. This hormone is present at shoot tip of the growing plant. It usually prefers to stay in shade or away from sunlight so when the sunlight falls on the stem directly from one side then it gets concentrated on the other side. Due to presence of more auxin, the shady side of the stem or shoot grows longer in comparison to the side of stem which is facing direct sunlight hence, makes the stem bend towards light.



34C. What is meant by positive phototropism and negative phototropism? Give one example of each type.

Answer

→ Positive phototropism is the movement of a plant part in response to a stimulus (light). If the movement of a plant part away from light then it is known as negative phototropism. The stem of a plant grows and bends towards light represents the positive phototropism while movement of root away from light inside the soil is an example of negative phototropism.

35A. Define geotropism. Give one example of geotropism.

Answer

→ Geotropism is the movement of a plant part in response to a stimulus (gravity).

35B. What is meant by 'positive geotropism' and 'negative geotropism? Give one example of each type. Draw a labeled diagram to illustrate your answer indicating the plant part which shows positive geotropism and the plant part which shows negative geotropism.

Answer

→ Positive geotropism is movement of a plant part towards the direction of gravity. For example, roots grow in the soil.
Negative geotropism is the movement of a plant part against the direction of gravity. For example, Stem or shoot grow outside the soil.

35C. Name one plant part which exhibits positive thigmotropism.

Answer

→ A tendril is a specialized leaf, petiole or stem with a threadlike shape. It is used by climbing plants for support and attachment. The tendrils grow towards the things they happen to touch and the phenomenon is known as thigmotropism.

36A. How does control and coordination take place in plants? How does it differ from that in animals?

Answer

→ Like humans and other animals, plants do not have a well-defined nervous system but they can sense things in their surroundings in the presence of various stimuli like light, gravity, water, touch etc. and respond them by different hormonal actions. The plants coordinate their behavior against environmental behavior by these hormones. This process is called coordination. These hormones are organic chemicals and play a vital role in different plant parts that results the movement of plant part in response to a stimulus. In animals, the control and coordination takes place in coordination of both nervous system and hormones.

36B. Name five stimuli which act on plants. Name the type of tropism produced by each one of these stimuli.

Answer

→ (i) Light is the stimulus in phototropism.
(ii) Gravity is the stimulus in geotropism.
(iii) Touch is the stimulus in thigmotropism.
(iv) Water is the stimulus in hydrotropism.
(v) Chemical is the stimulus in chemotropism.

36C. Define hydrotropism. Give one example of hydrotropism. State whether this example is of positive hydrotropism or negative hydrotropism. Illustrate your answer with the help of labeled diagram.

Answer

→ Hydrotropism is the movement of a plant part in response to a stimulus (water).
Example: The plant roots always move towards water hence shows positive hydrotropism.

37A. What is meant by positive tropism and negative tropism? Explain with examples.

Answer

→ Positive tropism is the growth of a plant part in response to a stimulus while negative tropism is the growth of a plant part is away from the stimulus.
Example: The roots of a plant grow towards gravity in soil represent the positive geotropism whereas stem of same plant grows against the gravity and represent the negative geotropism.

37B. Define thigmotropism. Give one example of thigmotropism.

Answer

→ Thigmotropism is the directional growth movement of a plant part in response to the stimuli (touch). Example: A tendril is a specialized leaf, petiole or stem with a threadlike shape. It is used by climbing plants for support and attachment. The tendrils grow towards the things they happen to touch.

37C. What is the difference between thigmotropism and thigmonasty? Name one plant which exhibits thigmotropism and one plant which exhibits thigmonasty. What behaviour (or responses) of these plants make you think that they exhibit thigmotropism and thigmonasty respectively?

Answer

→ Thigmotropism is the directional growth movement of a plant part in response to the stimuli (touch). Example - Tendrils
Thigmonasty is non-directional movement of a plant part in response to the stimuli (touch). Example – Mimosa pudica (Touch me not or Chui-mui plant)
Tendrils grow towards a stimulus (touch) and show directional movement and represent thigmotropism. In case of thigmonasty, the folding of leaves in Mimosa pudica (Touch me not or Chui-mui plant) is not depend on the direction of stimulus.

Control and Coordination - Lakhmir Singh Manjit Kaur Solutions Pg No. 94 Class 10 Biology

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Solutions of Control and Coordination Lakhmir Singh Manjit Kaur MCQ and HOTS Pg No. 94 Class 10 Biology

Solutions of Control and Coordination Lakhmir Singh Manjit Kaur MCQ and HOTS Pg No. 94 Class 10 Biology

Multiple Choice Questions (MCQs)-Pg-94

38. Which of the following is not a plant hormone?
A. auxin 
B. ascorbic acid 
C. cytokinin 
D. abscisic acid

Answer

→ Ascorbic acid, also known as Vitamin C, is a vitamin found in food particularly in citrus fruits and green vegetables.

39. One of the following plant hormones is responsible for the phenomenon of phototropism in plants. This is:
A. gibberellin 
B. eltroxin 
C. cytokinin 
D. auxin

Answer

→ Auxin, which is present at the tip of shoot, is responsible for the phenomenon of phototropism in plants.

40. The movement of a plant part in response to the force of attraction exerted by the earth is called:
A. hydrotropism 
B. geotropism 
C. chemotropism 
D. phototropism

Answer

→ Geotropism is the movement of a plant part in response to a stimulus (gravity).

41. The movement of sunflower in accordance with the path of the sun is due to:
A. photonasty
B. phototropism
C. hydrotropism
D. chemotropism

Answer

→ Phototropism is the movement of a plant part in response to a stimulus (light). Hence, the movement of sunflower in accordance with the path of the sun is due to phototropism.

42. The plant part which exhibits negative geotropism is:
A. root 
B. stem 
C. branch
D. leaves

Answer

→ Negative geotropism is the movement of a plant part against the direction of gravity. For example, Stem or shoot grow outside the soil.

43. A big tree falls in a forest but its roots are still in contact with the soil. The branches of this fallen tree grow straight up (vertically). This happens in response to
A. water and light
B. water and minerals
C. gravity and water
D. light and gravity

Answer

→ The roots show positive geotropism and stem or other aerial parts of plants show negative geotropism. Its reverse, the roots show negative phototropism while other aerial parts show positive geotropism.

44. Which of the following is not caused by a growth movement?
A. bending of the shoot of a plant in response to light
B. closing up of leaves of a sensitive plant on touching with an object
C. climbing up of a plant on an object by using tendrils
D. movement of the root of a plant towards a source of water

Answer

→ Closing up of leaves of a sensitive plant on touching with an object (also known as Thigmonasty) is not caused by a growth movement.

45. The root of a plant is:
Options -
(i) positively phototropic but negatively geotropic
(ii) positively geotropic but negatively phototropic
(iii) negatively phototropic but positively hydrotropic
(iv) negatively hydrotropic but positively phototropic
A. (i) and (ii)
B. (ii) and (iii)
C. (iii) and (iv)
D. (i) and (iv)

Answer

→ The root of plant grows in response to gravity inside the soil. Hence, it is positively geotropic but negatively phototropic.

46. The main function of the plant hormone called abscisic acid is to:
A. increase the length of cells
B. promote cell division
C. inhibit growth
D. promote growth of stem and roots

Answer

→ Abscisic acid is the growth inhibitor plant hormone.

47. The growth of tendrils in pea plants is due to the:
A. effect of sunlight on the tendril cells facing the sun
B. effect of gravity on the part of tendril hanging down towards the earth
C. rapid cell division and elongation in tendril cells that are away from the support
D. rapid cell division and elongation in tendril cells in contact with the support

Answer

→ The growth of tendrils in pea plants is due to the rapid cell division and elongation in tendril cells that are away from the support.

48. Which of the following phytohormone is not associated with the promotion of growth in plants?
A. auxin
B. abscisic acid
C. gibberellin
D. cytokinin

Answer

→ Abscisic acid is the growth inhibitor plant hormone.

49. The plant hormone which triggers the fall of mature leaves and fruits from the plant body is:
A. auxin
B. gibberellin
C. abscisic acid
D. cytokinin

Answer

→ Abscisic acid, the growth inhibitor plant hormone, triggers the fall of mature leaves and fruits from the plant body.

50. Which of the following terms denotes the movement of the root of a plant towards moisture in the soil?
A. thigmotropism
B. chemotropism
C. hydrotropism
D. geotropism

Answer

→ Hydrotropism is the movement of a plant part in response to water. The water is the stimulus in this process.

51. The growth of a pollen tube towards the ovule caused by a sugary substance as stimulus is an example of:
A. phototropism
B. chlorotropism
C. gravitropism
D. chemotropism

Answer

→ Due to chemical stimulus, the growth of a plant part is known as chemotropism. For example, a sugary substance can induce to the growth of pollen tube towards the ovule. Here, sugary substance works as a stimulus and this process represents the positive chemotropism.

52. The bending of the shoot of a plant in response to light is called:
A. geotropism
B. phototropism
C. thigmotropism
D. photonasty

Answer

→ The process of bending of a shoot towards light is known as phototropism.

53. The stimulus in the process of thigmotropism is:
A. touch
B. gravity
C. light
D. chemical

Answer

→ Thigmotropism is the movement of a plant part in response to touch. Touch is the stimulus in this process.

54. A growing seedling is kept in a dark room. A burning candle is placed near it for a few days. The top part of seedling bends towards the burning candle. This is an example of:
A. chemotropism
B. hydrotropism
C. phototropism
D. geotropism

Answer

→ The process of bending of a shoot towards light is known as phototropism.

55. Which of the following acts as a stimulus in the process of hydrotropism?
A. hydrocarbon
B. hydrogen oxide
C. hydrogen chloride
D. hydrogen peroxide

Answer

→ Hydrogen oxide (OH) acts as a stimulus in the process of hydrotropism.

56. The growth movement of a plant part in response to the touch of an object is called:
A. thigmonasty
B. hydrotropism
C. thigmotropism
D. geotropism

Answer

→ Thigmotropism is the movement of a plant part in response to touch of an object. Touch is the stimulus in this process.

57. The climbing organs of plants like tendrils grow towards any support which they happen to touch and wind around the support. This is an example of:
A. chemotropism
B. nastic movement
C. thigmotropism
D. geotropism

Answer

→ The process of winding of tendril around a support is known as thigmotropism.

58. The rate of growth in roots is decreased by one of the following plant hormones. This plant hormone is:
A. gibberellin
B. auxin
C. cytokinin
D. ethene

Answer

→ Auxin has adverse effect on growth rate of roots hence, it decrease the growth rate of roots.

59. When the leaves of a Mimosa pudica plant are touched with a finger, they fold up quickly. This is an example of:
A. chemotropism
B. thigmonasty
C. photonasty
D. thigmotropism

Answer

→ Thigmonasty is the non-directional movement of a plant part in response to the touch. The folding up of Mimosa pudica (touch me not or chui-mui) leaves when touching is an example of this process.

60. Dandelion flowers open the petals in bright light during the daytime but close the petals in dark at night. This response of dandelion flowers to light is called:
A. phototropism
B. thigmonasty
C. chemotropism
D. photonasty

Answer

→ Photonasty is the non-directional movement of a plant part (e.g. petals of flowers) in response to light. The opening and closing of petals of dandelion flowers in response to light intensity is an example of this process.

61. To which of the following directional stimulus roots of a plant do not respond?
A. moisture
B. candle light
C. touch
D. gravity

Answer

→ Touch is a directional stimulus roots of a plant do not respond.

62. One of the following is not caused by the growth related movement of the concerned plant part. This is:
A. phototropism
B. photonasty
C. thigmonasty
D. thigmotropism

Answer

→ Thigmonasty is the non-directional movement of a plant part in response to the touch. The folding up of Mimosa pudica leaves when touching is an example of this process.

63. The bending of the root of a plant away from a source of light is caused by a plant hormone called:
A. cytokinin
B. gibberellin
C. abscisic acid
D. auxin

Answer

→ Auxin is the hormone that causes phototropism in plants.

64. Most of the plant hormones promote plant growth. A plant hormone which inhibits growth is:
A. abscisic acid
B. ethene
C. ascorbic acid
D. cytokinin

Answer

→ Abscisic acid is the growth inhibitor plant hormone.

65. The movement of a shoot towards light is:
A. geotropism
B. hydrotropism
C. chemotropism
D. phototropism

Answer

→ The process of bending of a shoot towards light is known as phototropism.

66. The bending of the stem of a plant towards a source of light is caused by the action of a phytohormone known as:
A. abscisic acid
B. auxin
C. gibberellins
D. cytokinin

Answer

→ Auxin is the phytohormone which is responsible for the bending of the stem of a plant towards a source of light. This hormone is present at shoot tip.

67. Which of the following plant part exhibits negative phototropism?
A. root
B. branch
C. leaves
D. stem

Answer

→ Negative phototropism is the process in which roots of plants bend away from light.

68. Which of the following are not tropisms?
(i) growing of pollen tube in response to a sugary substance
(ii) folding up of leaves of sensitive plant in response to touch
(iii) winding of tendril around a support in response to touch
(iv) opening up of the leaves of a daisy flower in response to light
A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (iv)
D. (ii) and (iv)

Answer

→ Folding up of leaves of sensitive plant in response to touch is known as photonasty which is not a type of tropism. Opening up of the leaves of a daisy flower in response to light is also not an example of tropism.

Questions Based on High Order Thinking Skills (HOTS)-Pg-96

69. The chemical substance P is made and secreted by the meristematic tissue at the tip of stem (or shoot) of a plant. The chemical substance P is responsible for a phenomenon Q in plants in which the stem bends towards a source of light. The same chemical substance P has an opposite effect on the root of a plant. It causes the root of a plant to bend away from the source of light in a process called R.
(a) What is the chemical substance P?
(b) State whether P prefers to remains in the sunlight side of a stem or in shade.
(c) What is the effect of substance P on the rate of growth of (i) a root, and (ii) a stem?
(d) What is the name of process (i) Q, and (ii) R?
(e) What is the general name of chemical substances like P? Name another substance which belongs to this class of chemical substances.

Answer

→ (a) From the given question, the chemical substance P is Auxin which is produced at the shoot tip and can diffuse to other plant parts.
(b) Auxin moves to the darker side of the plant, causing the cells there to grow large.
(c) Auxin has adverse effect on growth rate of roots hence, it decrease the growth rate of roots. Unlike roots, the auxin has positive effect on growth rate of stem hence, it increases the growth rate of stem.
(d) Process Q is positive phototropism while process E is negative phototropism. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism.
(e) Chemical substance like P is Auxin, a Phytohormone or plant hormone. Like Auxin, Gibberellin is also an example of phytohormone.

70. A potted plant is growing in a transparent glass jar. In this plant, X and Y are the two growing parts having a lot of meristematic tissue. It is observed that the part X of this plant exhibits positive geotropism but negative phototropism. On the other hand, part Y of this plant exhibits negative geotropism but positive phototropism.
(a) Name the part X of plant.
(b) Name the part Y of plant.
(c) Which part of the plant, X or Y, will exhibit positive hydrotropism?
(d) Which part of the plant, X or Y, can have tendrils on it?

Answer

→ (a) Roots show positive geotropism and grow in the direction of gravity. In soil, they grow towards dark hence, show negative phototropism.
(b) Stem or shoot shows positive phototropism and grows towards the light. They grow in opposite direction of gravity hence, show negative geotropism.
(c) The plant roots (Part X) always move towards water hence shows positive hydrotropism.
(d) Tendrils grow towards a stimulus (touch) and show directional movement and represent thigmotropism. Stem (Part Y) can have tendrils on it.

71. There are three plants A, B and C. The flowers of plant A open their petals in bright light during the day but close them when it gets dark at night. On the other hand, the flowers of plant B open their petals at night but close them during the day when there is bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.
(a) Name the phenomenon shown by the flowers of (i) plant A, and (ii) plant B.
(b) Name one flower each which behaves like the flower of (i) plant A, and (ii) plant B.
(c) Name the phenomenon exhibited by the leaves of plant C.
(d) Name a plant whose leaves behave like those of plant C.
(e) Which plant/plants exhibit the phenomenon based on growth movements?

Answer

→ (a) (i) Plant A shows positive photonasty.
(ii) Plant B shows negative photonasty.
(b) (i) In the morning, a dandelion flower opens up its petals in bright light. This phenomenon is known is positive photonasty.
(ii) A Moonflower flower closes its petals at night. This phenomenon is known as negative photonasty.
(c) Thigmonasty is the non-directional movement of a plant part in response to the touch. The folding up of leaves of plant C when touching is an example of this process.
(d) The folding up of Mimosa pudica leaves when touching is an example of Thigmonasty process.
(e) Plant A and B exhibit the phenomenon based on growth movements.

72. While conducting experiments to study the effect of various stimuli on the plants, it was observed that the roots of a plant X grow and bend towards two stimuli A and B but bend away from a third stimulus C. The stem of the plant X, however, bends away from stimuli A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to too much weight of the earth. Keeping these points in mind, answer the following questions:
(a) What could stimulus A be?
(b) Name the stimulus B.
(c) What could stimulus C be?
(d) The branches of a fallen tree in a forest grow straight up in response to two stimuli. What could be these two stimuli out of A, B and C? Also name these two stimuli.

Answer

→ (a) Stimulus A could be water as roots show the positive hydrotropism.
(b) Stimulus B could be gravity as roots show the positive geotropism.
(c) Stimulus C could be light as roots show the negative phototropism.
(d) The two stimuli could be B (gravity) and C (light).

73. P and Q are two types of plants having weak stems which cannot stand upright on their own. The plants P and Q have organs R and S respectively which can grow towards any support which they happen to touch and wind around that support. It is- observed that organ R originates from the leaves of the plant whereas organ S originates directly from the stem of the plant.
(a) What is (i) R, and (ii) S?
(b) What is the name of growth movement exhibited by the organs R and S?
(c) Name the stimulus involved in this case.
(d) State whether the behaviour of organs R and S is a tropic movement or a nastic movement.
(e) Name one plant like P and another plant like Q.

Answer

→ (a) (i) R is a leaf tendril.
(ii) S is a stem tendril.
(b) A tendril is a specialized leaf, petiole or stem with a threadlike shape. It is used by climbing plants for support and attachment. The tendrils grow towards the things they happen to touch and the phenomenon is known as thigmotropism.
(c) Touch (support) is the stimulus involved in this case.
(d) behaviour of organs R and S is a tropic movement. Tropic movement is always in the direction of stimulus. All parts of a plant (roots, stem and leaves etc.) exhibit tropic movements.
(e) Pea plant is like P (leaf tendrils) and bitter gourd plant is like Q (stem tendrils).

74. The top part A of the flask-shaped reproductive organ X in the flower of a plant secretes a surgery substance into its lower part B which goes towards the bottom part C of the flask-shaped organ. When a tiny grain D coming from the top part E of another reproductive organ Y in the flower falls on part A, it grows a long tube F through the organ X in response to the sugary substance and reaches the bottom part C of flask shaped organ to carry out fertilisation.
(a) What is (i) organ X, and (ii) organ Y, inside the flower?
(b) Name parts (i) A (ii) B, and (iii) C, of flask-shaped organ.
(c) Name (i) grain D, and (ii) part E of organ Y.
(d) Name the tube F.
(e) What is the phenomenon of growing a long tube in response to a sugary substance in the process of fertilization in a flower known as?

Answer

→ (a) (i) Inside the flower, the organ X is carpel (a female reproductive organ).
(ii) Inside the flower, the organ Y is stamen (a male reproductive organ).
(b) (i) Part A of flask shaped organ is stigma.
(ii) Part B of flask shaped organ is style.
(iii) Part C of flask shaped organ is ovary.
(c) (i) Grain D of organ Y (stamen) is pollen grain.
(ii) Part E of organ Y (stamen) is anther.
(d) Tube F is the pollen tube.
(e) Due to chemical stimulus, the growth of a plant part is known as chemotropism. For example, a sugary substance can induce to the growth of pollen tube towards the ovule. Here, sugary substance works as a stimulus and this process represents the positive chemotropism.

75. P, Q, R and S are four major types of phytohormones. P is a phytohormone which functions mainly as a growth inhibitor. It promotes the wilting and falling of leaves. Q, R and S are phytohormones which all promote growth of plants in various ways. Q is responsible for the phenomenon of phototropism in plants. R is involved mainly in shoot extensions. The phytohormone S helps in breaking the dormancy of seeds and buds. What are P, Q, R and S? Give one reason each for your choice.

Answer

→ P is abscisic acid (a plant growth inhibitor hormone) and is responsible for the wilting and falling of leaves. Q is auxin which is responsible for the phenomenon of phototropism in plants as it is present at shoot tip. R is gibberellin which is responsible for enlargement of shoot. S is cytokinin which is responsible for breaking the dormancy of seeds and buds.

76. A potted plant having straight parts A and B was placed horizontally on its side as shown in Figure (i). After a few days it was observed that the parts A and B of the plant acquire new positions as shown:
(a) Name the phenomenon exhibited by the position of plant parts A and B in Figure (ii)
(b) Name the stimulus (other than sunlight) which causes plant part A to grow and bend upwards, and plant part B to bend downwards.

Answer

→ (a) The position of plant parts A and B shows negative geotropism and positive geotropism respectively.
(b) Gravity is the stimulus which causes plant part A to grow and bend upwards, and plant part B to bend downwards.

77. When the leaves of a sensitive plant are touched with a finger, they fold up and when light fades at dusk, the petals of a dandelion flower close.
(a) State one way in which the above two processes are similar.
(b) State two ways in which the above two processes differ.

Answer

→ (a) Above mentioned processes are similar i.e. both are nastic movements.
(b) In first process of folding of leaves of sensitive plant (thigmonasty), the stimulus is touch but in second process of folding of petals of dandelion flower (photonasty), stimulus is light. First process (thigmonasty) is not a growth movement but second process (photonasty) is a growth movement.

Control and Coordination - Lakhmir Singh Manjit Kaur Solutions Pg No. 115 Class 10 Biology

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Solutions of Control and Coordination Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 115 Class 10 Biology


Solutions of Control and Coordination Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 115 Class 10 Biology

Very Short Answer Type Questions-Pg-115

1. Name the two systems of control and coordination in higher animals.

Answer

→ Nervous system and endocrine system are the two systems of control and coordination in higher animals like human.

2. What are the two parts of the vertebrate nervous system?

Answer

→ Central nervous system and peripheral nervous system are the two parts of the vertebrate nervous system.

3. If we happen to touch a hot object unknowingly, we immediately pull back our hand. What is this type of action known as?

Answer

→ A reflex action occurs when the body responds to a stimulus without the involvement of the brain. Rapid pull out of hands from touching a hot surface and batting of eyelids are examples of reflex actions.

4. Name the three components of a neuron (or nerve cell).

Answer

→ A neuron, also known as nerve cell, is mainly consists of three components, namely cell body or soma, dendrites and axon.

5A. What are the short fibres of a neuron known as?

Answer

→ Dendrites are the short fibres of a neuron. They transmit impulses from synapses to cell body.

5B. What is the long fibre of a neuron known as?

Answer

→ Axon is the long fibre of a neuron. It carries the impulse away from the cell body.

6. Name the most important part of the human brain.

Answer

→ Cerebrum is the largest and uppermost portion of the human brain.

7. Which part of the brain maintains posture and balance of the body?

Answer

→ The cerebellum is the area of brain that controls motor movement coordination, balance, equilibrium and muscle tone.

8. State one function each of cerebellum and pons.

Answer

→ Function of cerebellum: It controls motor movement coordination, balance, equilibrium and muscle tone.
Function of pons: It regulates the breathing process. It also takes part in sensations such as hearing, taste and balance.

9. Name one hormone secreted by the pituitary gland.

Answer

→ Growth hormone (GH), also known as somatotropin, is secreted by anterior lobe of the pituitary gland.

10. Where are hormones made in the human body?

Answer

→ Hormones are the chemical messengers produced by glands in the endocrine system.

11. What is the name of the system of glands which produces hormones?

Answer

→ Hormones are the chemical messengers produced by glands in the endocrine system.

12. Which gland secretes the growth hormone?

Answer

→ Growth hormone (GH), also known as somatotropin, is secreted by anterior lobe of the pituitary gland.

13. Name the hormones secreted by (a) testes, and (b) ovaries.

Answer

→ (a) Testosterone hormone, also known as male sex hormone, is secreted by testes.
(b) Oestrogen and progesterone hormones are released by ovaries.

14. What are the scientific names for the following receptors in animals?
(a) receptors for light
(b) receptors for heat
(c) receptors for sound
(d) receptors for smell
(e) receptors for taste

Answer

→ (a) The scientific name for light receptor is photoreceptor.
(b) The scientific name for heat receptor is thermoreceptor.
(c) The scientific name for sound receptor is phonoreceptor.
(d) The scientific name for smell receptor is olfactory receptor.
(d) The scientific name for taste receptor is gustatory receptor.

15. Name the disease caused by the deficiency of insulin hormone in the body.

Answer

→ Diabetes mellitus, also known as hyperglycemia, is caused by the deficiency of insulin hormone in the body.

16. Name the disease caused by the deficiency of thyroxine hormone in the body.

Answer

→ Goitre, an enlargement of the thyroid gland, is caused by the deficiency of thyroxine hormone in the body.

17. Which halogen element is necessary for the making of thyroxine hormone by the thyroid gland?

Answer

→ Iodine is necessary for the making of thyroxine hormone by the thyroid gland which prevents goiter formation.

18. Why are some patients of diabetes treated by giving injections of insulin?

Answer

→ Some patients of diabetes treated by giving injections of insulin because it decreases the blood sugar level in the body.

19. What is the name of in-built 'arrangement' in our body which controls the timing and amount of hormones released by various endocrine glands in the body?

Answer

→ Feedback mechanism is a method of controlling the hormone production.

20. Name one gland each:
(a) which acts only as an endocrine gland.
(b) which acts only as an exocrine gland.
(c) which acts both as an endocrine gland as well as an exocrine gland.

Answer

→ (a) Thyroid is large, ductless gland present in the neck. It acts as an endocrine gland.
(b) Salivary glands present in and around the mouth and neck acts as an exocrine gland.
(c) Pancreas, an organ located in the abdomen, acts both as an endocrine gland as well as an exocrine gland.

21. What part does the diet play in helping us to have a healthy thyroid gland?

Answer

→ Diet provides iodine which makes keeps the thyroid gland healthy by making thyroxine hormone and also prevents goitre.

22. If sugar is detected in the urine of a person, name the disease he is suffering from.

Answer

→ In the diabetes (hyperglycemia) disease, the sugar level gets increased in the body.

23. Name two parts of the body which contain receptors of chemical stimuli.

Answer

→ Nose contains olfactory receptor whereas tongue has gustatory receptor.

24. Which part of the eye contains cells which are sensitive to light?

Answer

→ Eye retina contains cells which are sensitive to light.

25. What are the two main communications systems in an animal's body?

Answer

→ Endocrine system and Nervous system are the two main communications systems in an animal's body.

26. Which one term in each of the following includes the other three?
(a) thyroid, ductless gland, thymus, pituitary, ovary
(b) adrenalin, insulin, hormone, thyroxine, estrogen

Answer

→ (a) Thyroid, thymus, pituitary and ovary these all are ductless glands.
(b) Adrenalin, insulin, thyroxine and estrogen these all are hormones.

27. Which parts of the body form the central nervous system?

Answer

→ Spinal cord and brain form the central nervous system (CNS).

28. Give three examples of reflex actions.

Answer

→ Knee jerk reflex is an example of reflex action. The other examples include coughing and sneezing.

29. Why do you need iodine in your diet?

Answer

→ Iodine is required to synthesize of thyroxine hormone in the body hence necessary in our diet.

30. State whether coughing is a voluntary action or reflex action.

Answer

→ Coughing is an important defensive reflex that occurs through the stimulation of a complex reflex arc.

31. Fill in the following blanks with suitable words:
(a) The two examples of effectors are .................and .....................
(b) Our..................system allows us to react to our surroundings. Information from receptors passes along.................neurons to our brain. Our brain sends impulses along...........neurons to our muscles.
(c) A neuron which carries an impulse to the brain is called a .................... neuron.
(d) The neuron which carries a message for action to a muscle or gland is known as a.................... neuron.

Answer

→ (a) The two examples of effectors are glands and muscle.
(b) Our nervous system allows us to react to our surroundings. Information from receptors passes along sensory neurons to our brain. Our brain sends impulses along motor neurons to our muscles.
(c) A neuron which carries an impulse to the brain is called a sensory neuron.
(d) The neuron which carries a message for action to a muscle or gland is known as a motor neuron.

Short Answer Type Questions-Pg-116

32A. What are the various sense organs in our body?

Answer

→ In human body, there are 5 sense organs present. They are eyes, ears, nose, tongue and skin.

32B. What is meant by receptors and effectors? Give two examples of each.

Answer

→ A receptor is an organ or cell able to respond to heat, light or other external stimulus and transmit a signal to a sensory nerve. Example: Photoreceptor (a receptor which detects light) and phonoreceptor (a receptor which detects sound).
An effector is a muscle, gland or an organ capable of responding to a stimulus, especially a nerve impulse.

33A. What is spinal cord? What is its main function?

Answer

→ The cylindrical bundle of nerve fibres and associated tissue which is enclosed in the spine and connects nearly all parts of the body to the brain. It functions primarily in the transmission of neural signals between the brain and the rest of the body.

33B. Give the functions of medulla.

Answer

→ The medulla helps regulate breathing, heart and blood vessel function, digestion, sneezing and swallowing. It is a center for respiration and circulation.

34A. Name the three types of nerves which constitute the peripheral nervous system.

Answer

→ Spinal nerves, cranial nerves and visceral nerves are the three types of nerves which constitute the peripheral nervous system

34B. What is the difference between a reflex action and walking?

Answer

→ A reflex action is voluntary action which is a rapid and autonomic response to stimuli while walking is a voluntary action which requires our thinking and it’s in our control.

34C. How do we detect the smell of an incense stick (agarbatti)?

Answer

→ Agarbatti produces vapors on burning and generates a characteristics a fragrance which is detected by the olfactory receptors present in the nose. The electrical impulses are generated by the action of smell of agarbatti which sets off chemical reactions. Cerebrum, a sensory area present in the fore brain, receives these electrical impulses by which we can identify the smell of burning agarbatti.

35A. What substances are made by endocrine glands?

Answer

→ Hormones are produced by the endocrine glands. These hormones are responsible for different functions in the various organs of the body.

35B. What is the function of receptors and effectors in our body?

Answer

→ A receptor is an organ or cell able to respond to heat, light or other external stimulus and transmit a signal to a sensory nerve. It detects all the information from our surroundings and carries it to the nervous system.
An effector is a muscle, gland or an organ capable of responding to a stimulus, especially a nerve impulse.

36A. Name the hormones secreted by the following endocrine glands:
(i) Thyroid gland
(ii) Parathyroid glands
(iii) Pancreas
(iv) Adrenal glands

Answer

→ (i) Thyroxine hormone is secreted by the thyroid gland.
(ii) Parathormone is secreted by the parathyroid glands.
(iii) Insulin hormone is secreted by the pancreas gland.
(iv) Adrenaline hormone is secreted by the adrenal glands.

36B. Write the functions of testosterone and oestrogen hormones.

Answer

→ Testosterone is the principle male sex hormone and is responsible for reproductive growth and development in male vertebrates.
Oestrogen is the principle female sex hormone and is responsible for development of female secondary sexual characteristics.

37A. Write the names of the regions in hindbrain. Give one function of each region.

Answer

→ There are mainly 3 regions present in hindbrain. They are:
(i) Pons: It regulates the breathing process. It also takes part in sensations such as hearing, taste and balance.
(ii) Cerebellum: It controls motor movement coordination, balance, equilibrium and muscle tone.
(iii) Medulla: It is the controlling centre for reflex actions like coughing, sneezing and swallowing etc. It also controls various involuntary actions like blood pressure and peristaltic movements of the elementary canal.

37B. Name the functions of cerebrum.

Answer

→ Function of cerebrum: It is the largest part of the brain and also known as cortex. It is associated with higher brain function such as thought, memory and action.

38A. The human brain can be broadly divided into three regions. Name these three regions.

Answer

→ Forebrain, midbrain and hindbrain are three regions of human brain.

38B. What is cranium? What is its function?

Answer

→ Cranium is a part of the skull in which brain is located. It protects the brain from damage.

39A. How does chemical coordination take place in human beings?

Answer

→ In human beings and other animals, the chemical coordination takes place through the chemical messengers, called hormones. These hormones are produced by specific organs and carry through blood stream to other body parts. They are affected only a particular place of specific organ which is known as target organ. The organs control and coordinate different functions like growth, development, behavior, metabolism and secondary sexual characteristics etc.

39B. Why is the use of iodized salt advisable?

Answer

→ Iodine is required to synthesize of thyroxine hormone in the body. This hormone is secreted by the thyroid gland and is responsible for metabolism of carbohydrates, fats and proteins. Taking of iodine is advisable to prevent from goiter disease.

40. What is the function of insulin hormone? What types of patients are given insulin injections?

Answer

→ The insulin hormone lowers the blood sugar (glucose) level in the body. The people suffering from severe diabetes are treated by injecting insulin in the body.

41. Compare the nervous system and endocrine system (hormonal system) for control and coordination in humans.

Answer

→ Nervous system coordinates the activities of body. It is responsible for the coordination of biological activities inside the body through the network of specialised cells called neurons. It receives the information from surroundings and processes through neurons and interprets it and then responds accordingly.
Endocrine system is a discrete set of glands that secrete different types of hormones to the circulatory system in order to regulate the functions of the body. Each gland of the endocrine system is responsible for the secretion of different hormones which act as messengers between the nervous system and the organs of body.

42. State the functions of the following hormones:
(a) Thyroxine
(b) Adrenaline
(c) Growth hormone

Answer

→ (a) Thyroxine: Controls the metabolic rate of carbohydrates, fats and proteins in the body.
(b) Adrenaline: Regulates blood pressure, heart rate, breathing rate, and carbohydrate metabolism.
(c) Growth hormone: Controls the growth of human body.

43. Write the names of all the major endocrine glands present in the human body. Which of these glands also function as exocrine glands?

Answer

→ The endocrine glands present in the human body are:
(i) Pineal gland
(ii) Hypothalamus
(iii) Pituitary
(iv) Thyroid
(v) Parathyroid
(vi) Thymus
(vii) Pancreas
(viii) Adrenal glands
(ix) Testes (in males)
(x) Ovaries (in females).
Pancreas, testes and ovaries function as exocrine glands.

44. Match the hormones given in column I with their functions given in column II:
HormonesFunctions
(i) Thyroxine(a) Causes breasts to develop in females
(ii) Adrenaline(b) Causes the male to start producing sperms
(iii) Insulin(c) Prepares the body for an emergency
(iv) Estrogen(d) Controls the metabolic rate
(v)Testosterone(e) Regulates the amount of sugar in blood


Answer

→ The correct matching of hormones with their functions is as:
(i) – (d)
(ii) – (c)
(iii) – (e)
(iv) – (a)
(v) – (b)

45. A person walks across a room in bare feet and puts his foot on a drawing pin lying on the floor. He lets out a cry. Explain what happens in his nervous system in bringing about this response.

Answer

→ This is an example of reflex action. Here, drawing pin lying on the floor is the stimulus. The receptors located in the skin sense pain which triggers and impulse in a sensory neuron and transmits the message to the spinal cord. The impulse is passed onto a relay neuron which passes it to the motor neuron which passes the impulse to a muscle in the feet. It results contraction of muscle and pulling out feet away from the drawing pin.

46. In what ways are puberty and adolescence result of the activity of some glands in the human body?

Answer

→ In human beings, puberty and adolescence are the result of sex glands. Testes in males produce testosterone, a male sex hormone, which is associated with male puberty. In boys, this stage appears an age of 13-14 years. Ovaries in females produce oesterogen, a female sex hormone, is responsible for all the changes associated with female puberty. In girls, this stage is usually attains at an age of 10-12 years.

47. List three ways in which neurons are similar to other cells.

Answer

→ Neurons have cell membrane, nucleus and cytoplasm similar to other cells.

48. Explain the difference between each of the following pairs of terms:
(a) receptor and effector
(b) cerebrum and cerebellum

Answer

→ (a) A receptor is an organ or cell able to respond to heat, light or other external stimulus and transmit a signal to a sensory nerve.
An effector is a muscle, gland or an organ capable of responding to a stimulus, especially a nerve impulse.
(b) Cerebrum, a part of the forebrain, is responsible for controlling our thoughts, sensations, actions and movements.
Cerebellum, a part of the hindbrain, is responsible for maintaining the body posture and balance of the brain.

49. What is the difference between a voluntary and an involuntary action? Which kind of action is digestion? Explain your choice.

Answer

→ Voluntary action is controlled by the brain whereas involuntary action is controlled by the spinal cord. Riding a bicycle, dancing, and eating an apple are some examples of voluntary actions while breathing, flow of blood through our veins, blinking eye lids, heart beating, feeling emotions, growing for that matter are all involuntary actions.
Digestion is a kind of involuntary action.

50. What does CNS stand for? Which part of CNS:
(a) consists of two cerebral hemispheres, and
(b) has spinal nerves attached to it?

Answer

→ CNS stands for Central Nervous System.
(a) Cerebrum, a part of the forebrain, consists of two cerebral hemispheres.
(b) Spinal cord has spinal nerves attached to it.

51. Which hormone:
(a) prepares the body for action?
(b) controls the amount of glucose in blood ?
(c) gives boys a deep voice?
(d) gives girls soft skin?

Answer

→ (a) Adrenaline hormone prepares the body for action.
(b) Insulin hormone controls the amount of glucose in blood.
(c) Testosterone hormone gives boys a deep voice.
(d) Oestrogen hormone gives girls soft skin.

52. When you smell a favourite food your mouth begins to water (that is, you secrete saliva). Write down what the following are examples of:
(a) the smell of the food
(b) the cells in your nasal passages which perceive the smell
(c) the gland which is stimulated to secrete saliva.

Answer

→ (a) The smell of the food is a stimulus.
(b) Olfactory receptors are the cells in your nasal passages which perceive the smell.
(c) Salivary gland (effector) is the gland which is stimulated to secrete saliva.

Control and Coordination - Lakhmir Singh Manjit Kaur Solutions Pg No. 117 Class 10 Biology

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Solutions of Control and Coordination Lakhmir Singh Manjit Kaur LAQ, HOTS and MCQ Pg No. 117 Class 10 Biology

Solutions of Control and Coordination Lakhmir Singh Manjit Kaur LAQ, HOTS and MCQ Pg No. 117 Class 10 Biology

Long Answer Type Questions-Pg-117

53A. Name the structural and functional unit of nervous system.

Answer

→ A neuron is the structural and functional unit of nervous system.

53B. Draw a flow chart to show the classification of nervous system into various parts.

Answer

→ The below flow chart depicts the classification of nervous system into various parts.
Example: A student who is getting late for school suddenly sees his watch then starts walking fast autonomously. Here, when the eyes see the time they send the information to brain through the sensory nerves. After which the brain receives the information, analyses them and sends the instructions to walk faster to muscle of our legs through the motor nerves. Then, the muscle of the legs act simultaneously by which student walks faster.

53C. What is autonomic nervous system? What is its function?

Answer

→ Autonomic nervous system is self-governing nervous system which controls and regulates the functions of the internal organs of our body involuntarily.

53D. What is voluntary nervous system? Explain the working of voluntary nervous system with an example.

Answer

→ The voluntary nervous system helps us to take voluntary actions which are under the conscious control of the brain.
Example: A student who is getting late for school suddenly sees his watch then starts walking fast autonomously. Here, when the eyes see the time they send the information to brain through the sensory nerves. After which the brain receives the information, analyses them and sends the instructions to walk faster to muscle of our legs through the motor nerves. Then, the muscle of the legs act simultaneously by which student walks faster.

54A. What is a reflex action? Explain with the help of an example.

Answer

→ A reflex action is an involuntary, rapid response in the body to a stimulus.
Example: Moving our hand away on touching a hot bowl.

54B. Define reflex arc. Give the flow chart of a spinal reflex arc.

Answer

→ Reflex arc is the pathway taken by the nerve impulses in the reflex actions.

54C. How are involuntary actions and reflex actions different from each other?

Answer

→ All reflex actions are involuntary in nature but all involuntary actions are not reflexes. A reflex action is a rapid and autonomic response to a stimulus which is not under the voluntary control of the brain. Involuntary actions do not need thinking and also not performed by us knowingly. Sneezing and coughing are the examples of reflex actions whereas digestion and respiration are involuntary actions.

55A. What is the function of our nervous system?

Answer

→ The nervous system consists of the brain, spinal cord, sensory organs and all of the nerves that connect these organs with the rest of the body. Its main function is to establish the communication system between the organs of our body. It receives information from the surroundings, processes it, interprets it and then responds accordingly.

55B. What are the main organs of the human nervous system? Draw a labelled diagram to show the main organs of the human nervous system.

Answer

→ Brain, spinal cord and nerves are the main organs of the nervous system.
55C. How does the human nervous system work? Explain.

Answer

→ After affecting, the sense organ in our body sends the message (in the form of electrical impulses) to brain through the sensory neurons. The brain reads the signals and decides the necessary action to be taken out. Then, brain sends out the instructions through motor nerves to the body muscles of concerned part and then this part acts accordingly.

56A. What is a neuron? Draw a labelled diagram of a neuron.

Answer

→ A neuron, also known as nerve cell, is a cell that carries message between the brain and other body parts. It is the basic unit of the nervous system.

56B. What is a synapse? What happens at the synapse between two neurons? How are the messages carried across a synapse? Explain with the help of a labelled diagram.

Answer

→ In the nervous system, the synapse is a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter. Synapse between two neurons allows electrical impulses to pass in one direction only. The process is as follows: When the receptor sends an electrical impulse, it reaches at the end of the axon of sensory neuron. Then this electrical impulse releases a chemical, known as neurotransmitter, in very small amount into the synapse between two adjacent neurons. Neurotransmitter crosses the synapse and starts a similar electrical impulse in the dendrite of the next neuron. By this way, the electrical impulse passes from one neuron to the next across the synapse.

57A. Name two systems which taken together perform the functions of control and coordination in human beings.

Answer

→ Both nervous system and endocrine system are two systems which taken together perform the functions of control and coordination in human beings.

57B. What does the central nervous system in humans consist of? What is the job of the central nervous system?

Answer

→ The Central Nervous System (CNS) is made up of brain and spinal cord. The CNS is the main control center of the body. It takes in sensory information, organizes and synthesizes this input, then provides instructions for motor output to the rest of the body. In other words, it functions as the transmitter and receiver as well as the pathway for information flow and determines how the body responds to changes in its internal and external environment.

57C. Give the various functions of brain.

Answer

→ Functions of the brain: The brain is the command centre for the nervous system. It receives input from the sensory organs and sends output to the muscles. Intelligence, creativity, emotions, and memory are a few of the many things governed by the brain. It also controls the thoughts, memory and speech, movement of the arms and legs, and the function of many organs within the body.

58A. Write the names of five endocrine glands found in the human body. Name the hormones secreted by each gland.

Answer

→ (i) Pituitary gland secretes growth hormone.
(ii) Thyroid gland secretes thyroxine hormone.
(iii) Pancreas secreted insulin hormone.
(iv) Adrenal gland secretes adrenaline hormone.
(v) Testes secrete testosterone hormone.

58B. How do hormones reach the organs they control?

Answer

→ The endocrine glands are ductless glands which secrete their products as hormones. They release hormones directly into the blood stream. These hormones reach the target body part through the blood and then act on it.

58C. Name the gland which controls the secretion of hormones from the pituitary.

Answer

→ Hypothalamus gland controls the secretion of hormones from the pituitary.

58D. How does our body respond when adrenaline is secreted in large amounts into the blood?

Answer

→ The adrenaline hormone is secreted by adrenal gland, a gland present on top of the kidney. During emergency situations like anger, danger and stress etc., this hormone prepares our body to function at maximum efficiency. It increases blood flow into muscles, breathing and heart rate and causes liver to put more stored glucose into our blood which causes production of high energy. Thus, if adrenaline is secreted in large amounts then it prepares our body for action.

58E. Name the disease which occurs in adults due to the deficiency of iodine in the diet. What is the main symptom of this disease?

Answer

→ The Goitre disease occurs in adults due to deficiency of iodine in the diet. In this disease, the neck of the person gets swollen due to the enlargement of thyroid gland.

Multiple Choice Questions (MCQs)-Pg-117

59. A cell (or group of cells) in a sense organ which is sensitive to a particular type of stimulus is called:
A. interceptor
B. effector
C. receptor
D. acceptor

Answer

→ A receptor is an organ or cell able to respond to heat, light or other external stimulus and transmit a signal to a sensory nerve. Example: Photoreceptor (a receptor which detects light) and phonoreceptor (a receptor which detects sound).

60. Which of the following cannot be considered a receptor?
A. ear
B. nose
C. muscle
D. eye

Answer

→ Muscle is not a receptor.

61. One of the following acts as an endocrine gland as well as an exocrine gland. This one is:
A. salivary gland
B. pancreas
C. pituitary
D. parathyroid

Answer

→ Pancreas gland acts as an endocrine gland as well as an exocrine gland.

62. Which of the following helps in maintaining posture and balance of the human body?
A. cerebellum
B. cerebrum
C. medulla
D. pons

Answer

→ The cerebellum is the area of the hindbrain that controls motor movement, coordination, balance, equilibrium and muscle tone.

63. The number of pairs of nerves which arises from the spinal cord is:
A. 21
B. 31
C. 41
D. 51

Answer

→ There are total 31 pairs of nerves arise from the spinal cord.

64. Cerbellum, medulla and pons are the parts of:
A. mid-brain
B. hind-brain
C. forebrain
D. spinal cord

Answer

→ Hindbrain consists of cerebellum, medulla and pons.

65. Which of the following are cerebral reflexes?
(i) A person pulls away his hand on touching a hot object.
(ii) A person spits out immediately when a fly enters his mouth while talking.
(iii) A person walking bare foot lifts his foot at once on stepping on to a nail
(iv) A person's pupil contracts at once in the presence of bright light.
A. (i) and (ii)
B. (ii) and (iii)
C. (iii) and (iv)
D. (ii) and (iv)

Answer

→ A person spits out immediately when a fly enters his mouth while talking and a person's pupil contracts at once in the presence of bright light are cerebral reflexes.

66. Iodine is necessary for the synthesis of which of the following hormone?
A. adrenaline
B. auxin
C. thyroxine
D. insulin

Answer

→ Iodine is necessary for the synthesis of thyroxin hormone which is released by the thyroid gland and prevents from goiter disease.

67. Which of the following is a mis-matched pair?
A. adrenaline : pituitary gland
B. estrogen: ovary
C. pancreas : insulin
D. progesterone : ovary

Answer

→ Adrenaline hormone is released from adrenal gland.

68. One of the following is an incorrect statement about insulin. This is:
A. it is produced in pancreas
B. it regulates growth and development of the body
C. it regulates blood glucose level in the blood
D. its deficiency in the body will cause diabetes

Answer

→ Insulin does not regulate growth and development of the body.

69. The spinal cord originates from:
A. cerebrum
B. cerebellum
C. medulla
D. pons

Answer

→ The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the medulla oblongata.

70. The involuntary actions in the body are controlled by:
A. medulla in forebrain
B. medulla in hindbrain
C. medulla in spinal cord
D. medulla in midbrain

Answer

→ The involuntary actions in the body are controlled by medulla which is located in hindbrain.

71. Which of the following is not an involuntary action?
A. vomiting
B. chewing
C. heart beat
D. salivation

Answer

→ Chewing is a voluntary action.

72. Which of the following hormone prepares our body for action in emergency situations?
A. testosterone
B. growth hormone
C. adrenaline
D. insulin

Answer

→ The adrenaline hormone is secreted by adrenal gland, a gland present on top of the kidney. During emergency situations like anger, danger and stress etc., this hormone prepares our body to function at maximum efficiency.

73. One of the following controls the peristaltic movements of alimentary canal. This one is:
A. cerebrum
B. cerebellum
C. pons
D. medulla

Answer

→ The involuntary actions like peristaltic movements of alimentary canal in the body are controlled by medulla which is located in hindbrain.

74. The hormone which is associated with male puberty is called:
A. oestrogen
B. adrenaline
C. testosterone
D. progesterone

Answer

→ Testosterone hormone is secreted by testes and responsible for male puberty and other secondary sexual characters.

75. Which of the following endocrine gland does not occur as a pair in the human body?
A. adrenal
B. pituitary
C. testis
D. ovary

Answer

→ Pituitary gland does not occur as a pair in the human body. It has 2 lobes: anterior lobe and posterior lobe.

76. The junction between two adjacent neurons is called:
A. nerve junction
B. sensory junction
C. synapse
D. neuro-muscular joint

Answer

→ In the nervous system, the synapse is a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.

77. The life processes in humans are controlled and regulated by:
A. reproductive and endocrine systems
B. respiratory and nervous systems
C. endocrine and digestive systems
D. nervous and endocrine systems

Answer

→ Nervous system and endocrine system are the two systems of control and coordination in higher animals like human.

78. A doctor advised a person to take injection of insulin because:
A. his blood pressure was high
B. his heart beat was high
C. his blood sugar was high
D. his thyroxine level in blood was high

Answer

→ Insulin hormone decreases the blood sugar level.

79. All the voluntary actions of our body are controlled by:
A. cerebrum
B. cerebellum
C. pons
D. medulla

Answer

→ The part of the brain that controls voluntary actions is cerebrum, the largest part of the brain.

80. One of the following statements is not true about thyroxine. This is:
A. Thyroid gland requires iron to synthesise thyroxine
B. It regulates carbohydrate, protein and fat metabolism
C. Iodine is essential for the synthesis of thyroxine
D. Thyroid gland can enlarge due to lack of thyroxine

Answer

→ Thyroid gland requires iodine to synthesise thyroxine hormone.

81. Which of the following does not act as an endocrine gland as well as an exocrine gland?
A. testis
B. ovary
C. pituitary
D. pancreas

Answer

→ Pituitary gland does not act as an endocrine gland as well as an exocrine gland.

82. The part of brain which controls the involuntary actions such as heart beat, breathing, blood pressure, etc. is:
A. pons
B. medulla
C. cerebrum
D. cerebellum

Answer

→ The medulla oblongata connects the brain to the spinal cord and controls involuntary actions.

83. Dwarfism results due to:
A. excessive secretion of thyroxine hormone
B. excessive secretion of growth hormone
C. less secretion of adrenaline hormone
D. less secretion of growth hormone

Answer

→ Growth hormone (GH) is responsible for growth and development in human. Less secretion of this hormone results dwarfism.

84. The dramatic changes in body features associated with puberty are mainly because of the secretions of:
A. estrogen from testes and testosterone from ovary
B. estrogen from adrenal gland and testosterone from pituitary gland
C. testosterone from testes and estrogen from ovary
D. testosterone from thyroid gland and estrogen from pituitary gland

Answer

→ Testosterone hormone, also known as male sex hormone, is secreted by testes. Oestrogen and progesterone hormones are released by ovaries. Both testosterone and oesterogen are responsible for puberty in males and females respectively.

85. Which of the following statements is correct about receptors?
A. gustatory receptors detect taste while olfactory receptors detect smell
B. both gustatory and olfactory receptors detect smell
C. auditory receptors detect smell and olfactory receptors detect taste
D. olfactory receptors detect taste and gustatory receptors detect smell

Answer

→ Gustatory receptors are present in the tongue and are responsible for detecting taste. Olfactory receptors are present in the nose and responsible for detecting smell.

86. The part of brain which takes part in regulating respiration in the human body is:
A. medulla
B. pons
C. cerebellum
D. cerebrum

Answer

→ Pons of the human brain takes part in regulating respiration in the human body.

87. Electrical impulse travels in a neuron from:
A. dendriteaxon axon end Cell body
B. cell body dendriteaxon axon end
C. dendritecell body axonaxon end
D. axon endaxoncell body dendrite

Answer

→ The electrical impulse travels in a neuron from dendrite to cell body to axon to axon end.

88. In a synapse, chemical signal is transmitted from:
A. axon to cell body of the same neuron
B. cell body to axon end of the same neuron
C. dendrite end of one neuron to axon end of adjacent neuron
D. axon end of one neuron to dendrite end of adjacent neuron

Answer

→ In a synapse, chemical signal is transmitted from axon end of one neuron to dendrite end of adjacent neuron.

89. In a neuron, the conversion of electrical signal to a chemical signal occurs at/in:
A. dendrite end
B. cell body
C. axon end
D. myelin sheath

Answer

→ The conversion of electrical signal to a chemical signal occurs at axon end in a neuron.

90. One of the following gives the correct sequence of the components in a reflex arc. This is:
A. ReceptorMuscle sensory neuron Motor neuron Spinal cord
B. Receptors Motor neuron Spinal cord Sensory neuronMuscle
C. ReceptorsSpinal cord Sensory neuron Motor neuronMuscle
D. ReceptorsSensory neuronSpinal cord Motor neuronMuscle

Answer

→ The correct sequence of the components in a reflex arc is as follows:
ReceptorsSensory neuronSpinal cord Motor neuronMuscle

91. Which of the following statements are true?
(i) sudden action in response to something in the environment is called reflex action
(ii) sensory neurons carry electrical signals from spinal cord to muscles in a reflex action
(iii) motor neurons carry signals from receptors to spinal cord in a reflex action
(iv) the pathway of transmitting signals from a receptor to a muscle is a reflex action
A. (i) and (ii)
B. (i) and (iii)
C. (i) and (iv)
D. (i), (ii) and (iii)

Answer

→ Both statements (i) and (iv) are true.

92. The gustatory receptors of our body are in one of the following organs. This organ is:
A. ear
B. nose
C. tongue
D. skin

Answer

→ The gustatory receptors of our body are responsible for taste.

93. The olfactory receptors in humans are located in:
A. eyes
B. tongue
C. ears
D. nose

Answer

→ The olfactory receptors of our body are responsible for smell.

94. The contraction of pupil of the eye in the presence of bright light is an example of:
A. Voluntary reflex
B. Spinal reflex
C. Cerebral reflex
D. Adrenal reflex

Answer

→ The contraction of pupil of the eye in the presence of bright light is an example of cerebral reflex.

95. The faulty functioning of an endocrine gland can make a person very short or very tall. This gland is:
A. thyroid
B. pineal
C. adrenal
D. pituitary

Answer

→ The Growth hormone (GH) is secreted by pituitary gland. This hormone is responsible for controlling the growth and development in humans.

96. The underactive endocrine gland which causes goitre is:
A. pancreas
B. thyroid
C. adrenal
D. pituitary

Answer

→ The thyroxine hormone is secreted by thyroid gland. The lack of this hormone causes goiter in humans.

97. The endocrine gland whose malfunctioning causes diabetes disease is:
A. pituitary
B. pineal
C. parathyroid
D. pancreas

Answer

→ Pancreas gland secretes the insulin hormone which controls the blood sugar level and prevents from diabetes disease.

98. The use of iodized salt is recommended to prevent:
A. diabetes
B. gonorrhoea
C. dysentery
D. goitre

Answer

→ Goitre disease is caused to lack of iodine in the diet.

99. Which of the following are often called glands of emergency?
A. thyroid
B. pituitary
C. adrenal
D. pancreas

Answer

→ Adrenaline hormone, a hormone is released from adrenal gland, is also known as emergency hormone. During emergency situations like anger, danger and stress etc., this hormone prepares our body to function at maximum efficiency.

Questions Based on High Order Thinking Skills (HOTS)-Pg-120

100. P is a cell (or group of cells) in the human body which is sensitive to a particular type of stimulus and conveys the messages to CNS through nerves Q. On the other hand, R is a part of the human body which can respond to a stimulus according to the instructions sent from the CNS through nerves S.
(a) What is P? Name five organs which contain cells (or group of cells) like P.
(b) Name the nerves Q.
(c) What is R? Give two examples of R.
(d) Name nerves S.
(e) How do messages travel through the nerves Q and S?

Answer

→ (a) In above question, the P is a receptor. Eyes, ears, nose, tongue and skin contain cells like P (receptor).
(b) Nerves Q are sensory nerves.
(c) In above question, R is the effector. Muscles and glands are the examples of R (effectors).
(d) Nerves S are motor nerves.
(e) Messages travel through nerves Q (sensory nerves) and S (motor nerves) in the form of electrical impulses.

101. The human body contains a large number of cells A which are very long and branched, and look like electric wires. The longest branch of this cell is B whereas there are many small branches C. Any two A cells do not join to one another completely in the human body. There is a microscopic gap D between every pair of adjacent A cells through which electric impulses can pass by the release of a chemical substance.
(a) What are cells A?
(b) What is the name of (i) branch B, and (ii) branches C?
(c) What is the microscopic gap D known as?
(d) What is the function of cells like A in the human body?
(e) The cells A are of three types. Name the three types.

Answer

→ (a) In above question, cells A are neurons or nerve cells.
(b) (i) Branch B is axon and (ii) C branches are dendrites.
(c) The microscopic gap D is known as synapse.
(d) Cell A or Neurons transmit electrical signals or impulses to and from the central nervous system.
(e) Cell A or Neurons are of three types: Sensory neurons, motor neurons and relay neurons.

102. When we touch a hot plate unknowingly, then this heat is sensed by a receptor P present in our fingers. The receptor triggers an impulse in neuron Q which transmits the message to an organ R which is a part of the central nervous system. Here the impulse is passed on to a neuron S which in turn passes it to a yet another neuron T. The neuron T passes the impulse to a tissue U in our arm. The tissue U then contracts and pulls our hand away from the hot plate.
(a) What is the name of (i) receptor P (ii) neuron Q, and (iii) organ R?
(b) What is (i) neuron S, and (ii) neuron T?
(c) Name the tissue U.
(d) What name is given to the phenomenon in which hand is pulled away quickly from the hot plate?
(e) Name the effector in this whole process.

Answer

→ (a) (i) In above question, the receptor P is thermoreceptor.
(ii) The neuron Q is a sensory neuron and
(iii) The organ R is spinal cord.
(b) (i) The neuron S is a relay neuron.
(ii) The neuron T is a motor neuron.
(c) The tissue U is a muscle.
(d) Reflex action is phenomenon in which hand is pulled away quickly from the hot plate.
(e) Muscle of arm is an effector in this process.

103. The gland X which is located just below the brain in the human head secretes a chemical substance Y which controls the development of bones and muscles in the body of a person. Secretion of too little of substance Y as well as the secretion of too much of substance Y by the gland X leads to abnormal development of the body of a person.
(a) Name the gland X.
(b) What is the chemical substance Y?
(c) What happens if too little of substance Y is secreted?
(d) What happens if too much of substance Y is secreted?
(e) Name the system of glands in the human body of which gland X is a part.

Answer

→ (a) In above question, the gland X is pituitary gland.
(b) The chemical substance Y is Human growth hormone.
(c) If too little of substance Y is secreted then the person becomes a dwarf (very short) because growth hormone is responsible for growth and development in humans.
(d) If too little of substance Y is secreted then the person becomes a giant (very tall) because growth hormone is responsible for growth and development in humans.
(e) Gland X (pituitary gland) is a part of the endocrine system.

104. A and B are the two systems of control and coordination in the human body. The messages in system A are transmitted in the form of chemical substances C which travel comparatively slowly through the blood stream. The substances C are made in tissues D present in the head and trunk of human body. The messages in system B are transmitted very quickly in the form of electrical impulses through fibres E. The effect of messages transmitted by system B usually lasts for a much shorter time as compared to those transmitted by system A.
(a) Name the system A. What does system A consist of?
(b) Name the chemical substance C.
(c) What is tissue D? Name any five such tissues in the human body.
(d) Name the system B. What does system B consist of?
(e) Name the fibres E.
(f) State whether system A controls the working of system B or system B controls the working of system A.

Answer

→ (a) In above question, the system A is endocrine system. System A (Endocrine system) consists of glands.
(b) The chemical substance C is hormones.
(c) The tissue D is endocrine glands. Pineal, thyroid, pancreas, pituitary and ovaries are five such tissues in the human body.
(d) The system B is nervous system. The system B (nervous system) consists of brain, spinal cord and nerves.
(e) The fibre E is nerve fibres.
(f) The system B (nervous system) controls the functioning of system A (Endocrine system).

105. A cylindrical structure P in our body begins in continuation with medulla and extends downwards. It is enclosed in a bony cage Q and surrounded by membranes R. As many as x pairs of nerves arise from the structure P. The structure P is involved in the reflex actions of our body and conduction of nerve impulses to and from another organ S of our body with which it forms CNS.
(a) Name the structure P.
(b) Name (i) bony cage Q, and (ii) membranes R.
(c) How much is x?
(d) Name the organ S.
(e) What are the reflexes involving structure P only known as?

Answer

→ (a) In above question, the structure P is spinal cord.
(b) The bony cage Q is vertebral column and membranes R is meninges.
(c) The value of X is 31.
(d) The organ S is brain.
(e) The reflexes involving structure P (Spinal cord) only are known as spinal reflexes.

106. The pancreas is made up of two parts A and B. The part A secretes insulin whereas part B secretes pancreatic juice.
(a) Which part is functioning as an endocrine gland? Why?
(b) What is insulin and what effect does it have in the body?
(c) Name the disease which can be treated by giving insulin injections.
(d) What does pancreatic juice contain? Where does pancreatic juice go?
(e) Name the life process in which pancreatic juice is made use of.

Answer

→ (a) In above question, Part A is functioning as an endocrine gland because it secretes insulin hormone.
(b) Insulin is a hormone secreted by pancreas. It controls the blood sugar level and prevents from diabetes diseases.
(c) In diabetes, the patients are treated by injecting insulin injections.
(d) Digestive enzymes like pancreatic amylase, tryspin and lipase are present in the pancreatic juice. This pancreatic juice goes to small intestine.
(e) In digestion process, the pancreatic juice is made use of.

107. The gland A is attached to the wind pipe in the human body. The gland A makes and secretes a hormone B which controls the metabolism of carbohydrates, fats and proteins in the body. The non-metal element C is necessary for the formation of hormone B. The deficiency of C in the diet can cause a deficiency of hormone B in the body leading to a disease D in which the neck of a person appears to be swollen. People are advised to use salt E in cooking food so as to avoid disease D.
(a) Name (i) gland A, and (ii) hormone B
(b) What is the element C?
(c) Name one type of food which can provide sufficient C in the diet of a person.
(d) Name (i) disease D, and (ii) salt E.

Answer

→ (a) (i) In above question, the gland A is thyroid gland
(ii) The hormone B is thyroxine hormone which is released from the gland A (thyroid gland).
(b) The element C is iodine.
(c) Sea food like fish can provide sufficient element C (iodine) in the diet of a person.
(d) (i) The disease D is goiter.
(ii) The sale E is iodised salt.

108. A piece of thread was tied tightly around an animal's pancreatic duct. The animal subsequently had difficulty in digesting food but did not get diabetes. Explain.

Answer

→ After tying a piece of thread around the animal's pancreatic duct, it gets closed. By this, the digestive enzymes present in the pancreatic juice cannot reach into small intestine. Animals feel difficulty to digest the food in the absence of pancreatic juice. However, the pancreas secretes insulin hormone directly in the blood by which the animal does not get diabetes.

109. Which is the target organ of both adrenaline and insulin?
(a) heart
(b) kidney
(c) liver
(d) pancreas

Answer

→ Correct Answer: (c)
Both adrenaline and insulin act on liver in the body hence, the liver is the target organ for both these hormones.

110. A gland W is located just below the stomach in the human body. The gland W secretes a hormone X. The deficiency of hormone X in the body causes a disease Y in which the blood sugar level of a person rises too much. The person having high blood sugar is called Z.
(a) Name (i) gland W, and (ii) hormone X.
(b) What is the function of hormone X?
(c) Name (i) disease Y, and (ii) person Z.
(d) What advice would you like to give to a person who is suffering from disease Y due to faulty life-style?

Answer

→ (a) (i) In above question, the gland W is Pancreas.
(ii) The hormone X is insulin, secreted by gland W (pancreas).
(b) The hormone X (insulin) controls the blood sugar level and prevents from diabetes disease.
(c) (i) The disease Y is diabetes and (ii) the person Z is known as a diabetic person.
(d) In disease Y (diabetes), the patient should reduce his weight, take balance and control diet, avoid intake of more sugar in meal, do regular physical exercise and yoga, go for routine medical checkup and take medicines regularly.

111. There are two similar glands P which are located on the top of two similar organs Q in the human body. The glands P are often called glands of emergency and they secrete a hormone R into the blood stream. The hormone R is secreted in large amounts when a person is frightened. It brings about temporary changes in the body which allow a lot of substance S from the liver to go into blood so as to provide a lot of energy in a very short time. This helps the person concerned to fight back or run away from the frightening situation. What are P, Q, R and S?

Answer

→ (i) In above question, the gland P is adrenal glands.
(ii) The organ Q is kidneys.
(iii) The hormone R is adrenaline hormone
(iv) The substance S is glucose.

112. The two glands A and B which occur in pairs, are present in the endocrine system of humans. The pair of glands A is found only in females whereas the pair of glands B occurs only in males. The glands A make and secrete two hormones C and D whereas glands B make and secrete only one hormone E. In addition to hormones, glands A make gametes F whereas glands B make gametes G.
(a) What are glands A?
(b) What are hormones C and D?
(c) What are glands B? Name the hormone E.
(d) What are gametes (i) F, and (ii) G?
(e) Which event in the life of males and females is associated with the secretion of hormones C, D and E?

Answer

→ (a) In above question, the glands A are ovaries.
(b) The hormone C is oesterogen whereas hormone D is progesterone.
(c) The glands D are Testes. The hormone E is testosterone (a male sex hormone) released from gland D (testes).
(D) (i) The gametes F are ova or eggs.
(ii) The gametes G are sperms.
(e) In both males and females, puberty is associated with the secretion of hormones C (oesterogen), D (progesterone) and E (testosterone).

113. The organ A which is located inside the skull of our body is protected by a bony box Band it is surrounded by three membranes C. The space between the membranes is filled with a liquid D which protects the organ A from mechanical shocks. The organ A in combination with another organ E makes up the central nervous system.
(a) What is organ A?
(b) What are (i) B (ii) C, and (iii) D ?
(c) Name the organ E.
(d) While walking barefooted, if we happen to step on a sharp piece of stone, we immediately lift our foot up. Which of the two organs, A or E, is directly involved in this action?
(e) If we step out from a darkened room into bright sunshine, we close our eyes for a moment. Which of the two organs, A or E, is directly involved in this action?

Answer

→ (a) In above question, the organ A is brain.
(b) (i) The membrane B is cranium or skull.
(ii) The membrane C is Meninges.
(iii) The membrane D is cerebrospinal fluid.
(c) The organ E is spinal cord.
(d) The organ E (spinal cord) is directly involved in the action mentioned in the question.
(e) The organ A (brain) is directly involved in the action mentioned in the question.

114. Write down the following in the correct order for a simple reflex arc:
(a) impulse travels in motor fibre
(b) impulse travels in sensory fibre
(c) effector organ stimulated
(d) impulse crosses synapse

Answer

→ The pathway taken by nerve impulses in a reflex action is called a reflex arc. It is an automatic response to a stimulus. When a stimulus is given to a receptor, the receptors produce an impulse in the sensory fibre. The sensory fibre carries this message in the form of an electrical stimulus across the synapse. From the synapse, the impulse travels in the motor fibre and stimulates the effector organ to produce the desired response.
The correct order for a simple reflex arc is:
(b) →(d) → (a) → (c).

115. Explain why, the tongue may be considered to be both a receptor and an effector organ.

Answer

→ Tongue has taste buds hence, it is considered as a receptor. Taste buds act as receptors (gustatory receptor) for different kinds of taste. Tongue is a muscular organ having muscles which can respond to a stimulus hence, it is also considered to be an effector.

NCERT Solutions for Class 11th: Ch 9 Peace

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NCERT Solutions for Class 11th: Ch 9 Peace Political Science Political Theory

Exercises

Page No: 127

1. Do you think that a change towards a peaceful world, needs a change in the way people think? Can mind promote peace and is it enough to focus only on the human mind?

Answer

Peace is the central theme of all religion. We think from our minds and this is the place where all conflicts arises. So if people can think from different irrespective then we can take step towards a peaceful world. However, the mind by itself is not enough to promote peace because you cannot control the outside harmful elements of the society Thus, the creation of a peaceful society requires the elimination of these harmful elements.

2. A State must protect the lives and rights of its citizens. However, at times its own actions are a source of violence against some of its citizens. Comment with the help of some examples.

Answer

Each state sees itself as an independent and supreme entity, it tends to protect its own perceived
self-interest. The state is expected to use its force, its army or its police, to protect its citizens, in practice these forces could be deployed against its own members to suppress dissent. This is most
clearly evident in authoritarian regimes and military dictatorships.

•  In America, until 1865, slavery existed. In Germany, during Hitler's regime genocide was commited. 
• In South Africa, policy of racial discrimination was followed until 1992. 
• In certain countries the policy of racial discrimination is followed even today. 
• Immigrants from Asia, Latin America and Africa are not treated well in western countries. 
• In Myanmar, under the military regime, many democratic leaders and citizens were  put in jail. Aung San Suu Kyi, the leading opposition leader was kept under House arrest from 1989 to 1995.

3. Peace can be best realised when there is freedom, equality and justice. Do you agree?

Answer

Yes, Peace can be best realised when there is freedom, equality and justice. Freedom allows people to express themselves freely on the other hand equality and justice help in removing the grounds for conflict. Through equality, we can ensure get equal treatment and reduce the chance of negative thinking. Justice ensures the prevention of oppression of individuals and groups based on class, gender, etc.

• In a democracy, where freedom, justice and equality is the right of every individual, we see people are more peaceful as compared to Iraq, Iran and North Korea. These ideals help in building a society that cooperate with others.

4. Use of violence does not achieve just ends in the long run. What do you think about this statement?

Answer

Use of violence does not achieve just ends in the long run as it tends to spin out of control, leaving behind a trail of death and destruction. Violence involved in forcefully removing oppressors, liberation struggle and self-defence is often justified. However, the removal of oppressors by the oppressed class through violent struggle leads to another cycle of violence fuelled by a feeling for revenge.
It is for this reason that pacifists, who considerpeace to be a supreme value, take a moral stand against the use of violence even for attaining just ends. They too recognise the need to fight oppression but they advocate the mobilisation of love and truth to win the hearts and minds of the oppressors.

5. Differentiate between the major approaches, discussed in the chapter, to the establishment of peace in the world.

Answer

The major approaches that are discuss in the chapter to the establishment of peace in the world are:

• The First Approach: It is related centrally to states which favours sovereignty and deals with fair competition between the states. Its chief concern is with the proper management of this competition and with the containment of possible conflict.

• The Second Approach: It put emphasis on increasing social and economic cooperation among nations. The economic integration and interdependence that leads to political unification.

• The Third Approach: It considers state as passing phase of human history. It cisualises the state as a transitory system and the emergence of a global community surpassing the state system to maintain world peace. The process of globalisation has accelerated the process by reducing the influence of state and diluting the concept of sovereignty.

Notes of Ch 7 Nationalism

NCERT Solutions for Class 11th: Ch 10 Development

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NCERT Solutions for Class 11th: Ch 10 Development Political Science Political Theory

Exercises

Page No: 127

1. What do you understand by the term development? Would all sections of society benefit from such a definition of development?

Answer

Development conveys the ideas of improvement, progress, well-being and an aspiration for a better
life. Through its notion of development a society articulates what constitutes its vision for the society as a whole and how best to achieve it. This definition of development would benefit all the sections of society as it shows the basic need which is the food, shelter, education, clothes etc.

However, development has become the subject of considerable controversy today. It has unfortunately often come to be identified with achieving pre-set targets, or completing projects like dams, or factories, hospitals, rather than with realising the broader vision of development which the society upholds. In the process some sections of society may have benefited while others may have had to suffer loss of their homes, or lands, or way of life, without any compensatory gains.

2. Discuss some of the social and ecological costs of the kind of development which has been pursued in most countries.

Answer

Social Costs of Development

• A large number of people have been displaced from their homes and localities due to the construction of big dams, industrial activities and mining activities, or other projects.

• Displacement causes loss of livelihood and increased impoverishment along with destruction of local culture and community life.
• Displacement of rural agricultural communities has resulted in increased number of urban and rural poor and has brought them into the category of marginalised people.

• It is responsible for many struggles and social disorganisation.

Ecological Costs of Development

• The model of development we are pursuing is heavily dependent on the increasing use of energy which is currently generated in the world is from non-renewable sources like coal or petroleum.

• The ice in the Arctic and Antarctic is melting because of increased emission of greenhouse gases into the atmosphere and this has the potential to cause floods and actually submerge low lying areas like Bangladesh and the Maldives.

• Air pollution is already a problem which does not discriminate between the rich and the poor.

• Loss of forests affects the poor who use forest resources for a variety of subsistence needs like firewood, medicinal herbs or food.

• Drying up of rivers and ponds and falling ground water levels means that women have to walk longer in order to procure water.

• Large tracts of the Amazon rainforests are being deforested in order to provide for the increased consumer needs.

3. What are some of the new claims for rights which the process of development has generated?
Answer

• The protection of people affected by development from the state and the society as a whole.

• The right of people to be consulted about decisions that affect their lives.

•The right to livelihood of people when their regular livelihood activities are threatened by developmental activities.

• Rights of communities, particularly tribal and aboriginal, to the use of natural resources.

• Rights of future generations to the resources that are common to the entire humanity.

4. What would be the advantages of democracy over other forms of government for ensuring that decisions regarding development are made to promote the common good?

Answer

• In a democracy conflicts over resources, or different visions of the good life, are resolved through debate and a respect for the rights of all. These cannot be imposed from the higher authorities.

• Democracy ensure participation of local decision-making bodies to take decisions about development projects in the local area.

• The people have to be consulted on issues which most affect them and it should be possible to reject projects which can adversely affect the community.

• A decentralised approach to development makes it possible to use various kinds of technologies traditional and modern in a creative manner.

5. In your view how successful have popular struggles been in making the state responsive to the social and environmental costs of development? Discuss with examples.

Answer

The popular struggles such as Narmada Bachao Aandolan and Chipko Movement tired to make state responsive in their own way.

• Narmada Bachao Aandolan is a social movement against a number of large dams being built across the Narmada River. It first started as a protest for not providing proper rehabilitation and resettlement for the people who have been displaced by the construction of Sardar Sarovar Dam. Later on, the movement turned its focus on the preservation of the environment and the eco-systems of the valley. A large forest was submerged during the construction and many people were displaced. This social movement has been partially successful in reducing the height of Sardar Sarovar Dam.

• Chipko Movement main objective was to protect the trees on the Himalayan slopes from the axes of contractors of the forest. This movement against deforestation was successful in Uttrakhand. The people hugged the trees and stopped the contractors from cutting them down. This ecological movement also secured the livelihood of the local people who are depended on these forests.

Notes of Ch 7 Nationalism

Summary of Wind NCERT Class 9th

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Summary and Explanation of Wind Beehive Class 9

Wind Poem by Subramania Bharti

In this poem, the poet has very beautifully expressed his ideas about both the destructive and constructive aspects of the wind. The wind is often satirical of weak men. Wind symbolizes the difficulties that are faced in life. When we have the endurance to bear the difficulties of life we can overcome each challenge but if we are weak and unstable we succumb to the difficulties of life.

Stanza 1
Wind, come softly.
Don’t break the shutters of the windows.
Don’t scatter the papers.
Don’t throw down the books on the shelf.

The poet is addressing wind. Wind has been personified here. The poet is asking wind not to do destruction to his things. The poet asks wind to come softy and tells the wind to not break the shutters of windows. She also said the wind to not throw the books around, as wind usually do.

Stanza 2
There, look what you did — you threw them all down.
You tore the pages of the books.
You brought rain again.
You’re very clever at poking fun at weaklings.
Frail crumbling houses, crumbling doors, crumbling rafters,
crumbling wood, crumbling bodies, crumbling lives,
crumbling hearts —
the wind god winnows and crushes them all.

The wind didn’t listen to the poet. Wind did the destruction. It tore the pages of books. It brought the rain. It destroyed the weak houses, door and hearts. The wind god has crushed them all. The poet, therefore, curse the wind for the destruction it did. She told the wind that it felt good by making fun of weak.

Stanza 3
He won’t do what you tell him.
So, come, let’s build strong homes,
Let’s joint the doors firmly.
Practise to firm the body.
Make the heart steadfast.
Do this, and the wind will be friends with us.
The wind blows out weak fires.
He makes strong fires roar and flourish.
His friendship is good.
We praise him every day.

Poet now realizes that it is nature of wind to flow. No one can tell wind to do what to do and what not to do.  The poet realizes we need to be strong to face the wind. What we can do is to build strong homes. Join doors and windows firmly. Make ourselves strong. Make our heart strong.

NCERT Solutions of Wind Poem by Subramania Bharti

Summary of Evelyn Glennie Listens to Sound without Hearing it Class 9th Beehive

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Summary and Explanation of Evelyn Glennie Listens to Sound without Hearing it- The Sound of Music I (Character Sketch and Quick Revision Notes)

Character Sketch of Evelyn Glennie

Evelyn was a determined and hardworking girl. With her rock strong will power she overcame the obstacle that was presented by Nature. In childhood she lost her hearing capabilities gradually. At the age of eleven year, her hearing power was severely damaged. In spite of her handicap she did not want to give up. She took music as her passion. Her teachers discouraged her but percussionist Ron Forbes guided her. She joined a three year course at Royal Academy of Music. She captured most of top awards at the Royal Academy. She is the world’s most sought multiplayer of drums and tables. She is the shining example of determination.

Summary of the The Sound of Music I

Evelyn Glennie is a multi - percussionist, who can play thousands of instruments to perfection, a most sought after musician internationally. Surprisingly, she achieved this status in spite of her disability, she was profoundly deaf. But she learnt to listen with her body instead of the ears. She feels the sound through her body.

Evelyn was eleven years old when it was discovered that she had a hearing problem. She wanted to pursue her career in music, but her teachers discouraged her. It was Ron Forbes who recognized her potential and supported her. He advised her not to listen through her ears, but try to sense it in some other way. This proved to be the turning point. She learnt to open her body and mind to the sounds and vibrations. After that she never looked back. She had mastered the art of interpreting different vibrations of sound on her body.

She joined the prestigious Royal Academy of Music and scored the highest marks in the history of the Academy. She worked hard and with determination against all odds and got right to the top. In 1991, she was presented with the Royal Philharmonic Society's prestigious "Soloist of the year award". Apart from the regular concerts, Evelyn gave free concerts in hospitals, prisons and also to aspiring young musicians. She became a source of inspiration for deaf and other handicapped children. She inspired them and made them believe that if Evelyn could do, so could they.

Quick Revision Notes

  • Evelyn Glennie was 8, when first time her hearing disability was noticed by her mother.
  • At the age of 11, her disability was discovered at school. 
  • She wants to do career in Music, her teachers discouraged her.
  • Fortunately she met Ron Forbes, the percussionist, who identified her potential & supported in achieving her goal.
  • He trained Evelyn to sense the music through different parts of our body.
  • Suddenly she was excited to feel the vibrations in every part of her body.
  • Evelyn followed him like an obedient student and in the meantime she had learnt to open her body & mind to sounds and vibrations.
  • After this, she never looked back.
  • Evelyn joined the famous Royal Academy of Music, worked hard with strong determination. Suddenly she got to top.
  • In 1991, she bagged the Royal Philharmonic Society’s prestigious “Soloist of the Year Award”. She toured round the world for her concerts with a very hectic schedule and became a kind of workaholic.
  • Apart from this, she gives free concerts in prison & hospitals. Evelyn soon became shining super star & inspiration for not only the disabled ones but for all.
  • She achieved more than most people twice her age.
  • Evelyn has earned great name in Orchestra. She has inspired those who are handicapped & made them believe that if Evelyn could do that, why not they.

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