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Section B

Q. 17. Name any two types of asexual reproduction. 1

Ans. Fission and Budding.

Q. 18. State an instance where human intervention saved the forests from destruction. 1

Ans. ‘The Chipko Andolan’ is an example of the contribution of common people towards the conservation of forests. The Andolan originated from a remote village ‘Reni’ in Garhwal in the early 1970s in which villagers clasped the tree trunks with their arms to prevent them from being cut down.

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. You have two solar cookers, one covered by a plane transparent glass sheet and the other kept open. Which of the two solar cookers will be more efficient and why? 2

Ans. The solar cooker covered by a plane transparent glass sheet is more effective than the solar cooker which is kept open. This is because once the sun’s heat rays enter the cooker box which is covered, the heat rays get trapped in the box due to which the temperature in the solar cooker rises considerably.

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
Delhi		Outside Delhi		Compartment Delhi		Outside Delhi		Foreign
	Set 1 (PDF)		Set 1 (PDF)		Set 1		Set 1		Set 1 (PDF)
					Set 2		Set 2
					Set 3		Set 3