Answer key sample paper 2023-24 science

Section -A

1. (b) Barium sulphate 

2. (b)Colourless. 

Explanation: Since zinc is more reactive than copper, it displaces copper from copper sulphate solution to generate a colourless zinc sulphate solution.

3. (d) NaHCO3 (sodium bicarbonate) is a mild non-corrosive basic salt. It is commonly known as baking soda.

4. (a) sodium

5. (b) 

6. (d) The atomic number of an element which forms basic oxide is 11(2,8,1). The element is sodium.

7. (c) 14 

8. (b) mushroom because it is a saprotrophic.

9. (a) tongue has gustatory receptor.

10. (c) vegetative propagation

11. (c)The height of a plant is regulated by Growth hormones under the influence of the enzymes coded by a gene. Explanation: Under the control of the enzymes that the gene codes for, growth hormones control the plant's height.

12. (c) lack of oxygen and formation of lactic acid.

13. (d)

14. (c) scattering of light

15. (c)

16. (a) broken down by biological process

17. (d)

18. (a) 

19. (d)

20. (a)