CBSE Guess > Papers > Question Papers > Class X > 2009 > Science > Science 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. Q. 18. Name the plant hormones which help/promote Ans. (i) Cytokinins help/promote cell devision. Q. 19. Name any two forest products, each of which is the basis for some industry. 1 Ans. (i) Wood. It is used in timber industry, paper mills etc. Q. 20. What is nuclear energy? State its one advantage. 2 Ans. The energy released during a nuclear reaction is called nuclear energy. The energy released is mainly in the form of heat. Advantage of nuclear energy. A small amount of mass of nucleus is destroyed during a controlled nuclear reaction which gets converted into a tremendous amount of energy to produce electricity. 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: Q. 22. List four advantages of using solar cells. 2 Ans. Advantages of using solar cells:
CBSE 2009 Question Papers Class X |