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प्रश्न
What are the causes for the extinction of animals?
उत्तर
- Forests are destroyed for human needs.
- More animals are hunted for their horns, skin, teeth, and many other valuable products.
- Pollutions like air pollution and water pollution affect the animals.
- Sometimes animals are taken to new habitats by people. They cannot survive there.
- Pesticides and chemicals are used to get rid of insects, pests, or weeds, poison the plants and animals.
- Natural disasters like floods, cyclones, and fire also destroy animals.
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संबंधित प्रश्न
What do you mean by DNA?
Define reproduction.
Where is DNA found in a cell ?
State the importance of DNA copying.
Why is variation beneficial to the species but not necessarily for the individual?
Which life process ensures that a plant or animal species will not disappear from this earth?
What is the name of the reproductive process :
which involves two parents?
What is the name of the reproductive process :
which involves only one parent?
Write down the different methods of asexual reproduction.
Match the organisms given in column I with the methods of reproduction/propagation given in column II :
| Column I | Column II | |
| (i) Plasmodium | (a) Spore formation | |
| (ii) Spirogyra | (b) Leaves | |
| (iii) Jasmine | (c) Regeneration | |
| (iv) Apple tree | (d) Budding | |
| (v) Bryophyllum | (e) Binary fission | |
| (vi) Potatoes | (f) Layering | |
| (vii) Rhizopus | (g) Fragmentation | |
| (viii) Hydra | (h) Tubers | |
| (ix) Planaria | (i) Cuttings | |
| (x) Leishmania | (j) Multiple fission | |
| (xi) Sugar cane | (k) Grafting | |
| (xii) Rose |
What are the two general methods of reproduction in organisms?
Asexual reproduction is :
(a) a fusion of specialised cells
(b) a method by which all types of organisms reproduce
(c) a method producing genetically identical offspring
(d) a method in which more than one parent are involved
In the list of organisms given below, those which reproduce by the asexual method are :
(i) banana
(ii) yak
(iii) yeast
(iv) Amoeba
(a) (ii) and (iv)
(b) (i), (iii) and (iv)
(c) (i) and (iv)
(d) (ii), (iii) and (iv)
The offsprings formed by asexual reproduction method have greater similarity among themselves because :
(i) asexual reproduction involves only one parent
(ii) asexual reproduction involves two parents
(iii) asexual reproduction involves gametes
(iv) asexual reproduction does not involve gametes
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (i) and (iv)The offsprings formed by asexual reproduction method have greater similarity among themselves because :
(i) asexual reproduction involves only one parent
(ii) asexual reproduction involves two parents
(iii) asexual reproduction involves gametes
(iv) asexual reproduction does not involve gametes
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (i) and (iv)
State whether the following statement is true (T) or false (F):
Producing life is called respiration.
Explain the role of DNA in the process of reproduction of the cell.
What is morula?
What is the function of inner cell mass?
The plant which propagates with the help of its leaves is ______.
How is reproduction in Hydra different from that in Amoeba?
