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Section B

Q. 17. A young green plant receives sunlight from one direction only. What will happen to its shoots and roots? 1

Ans. (1) The roots bend away from light.
(2) The stem bends towards the light.

Q. 18. Mention the mode of reproduction used by (a) Amoeba (b) Planaria 1

Ans. (1) Amoeba → binary fission
(2) Planaria → regeneration

Q. 19. What are the two kinds of natural resources? 1

Ans. Two kinds of natural resources are:
(1) Renewable
(2) Non-Renewable.

Q.20. Draw a diagram of a nerve cell (neuron) and label on it the following: 2
(a) Nucleus (b) Dendrites

Ans. Diagram: See Q.1 (S.A.T.), Chapter 7. [Page 76

Q. 21. Name the information source of making proteins in the cell. State two basic events in reproduction. 2

Ans. The information source of making proteins in cell is DNA.

Two basic events in reproduction are:
(i) The creation of a DNA copy. Here the cells use chemical reactions to build copies of their DNA. This creates two copies of the DNA in a reproducing cell.
(ii) DNA copying is accompanied by the creation of an additional cellular apparatus, and then the DNA copies separate, each with its own cellular apparatus. Effectively, a cell divides to give rise to two cells.

Q. 22. List four advantages of using solar cells. 2

Ans. Advantages of using solar cells:
(i) They have no moving parts.
(ii) They require almost no maintenance.
(iii) They work quite satisfactorily even without using any light focussing device.
(iv) They can be set up in remote, inaccessible and very sparsely inhabited areas where the laying of usual power transmission lines is difficult and expensive.

Science 2009 Question Papers Class X
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	Set 1 (PDF)		Set 1 (PDF)		Set 1		Set 1		Set 1 (PDF)
					Set 2		Set 2
					Set 3		Set 3