CBSE Class 10 Answered

(a) The steps that takes place in chloroplast during photosynthesis are:

(i) Absorption of light energy by chlorophyll.

(ii) Conversion of light energy into chemical energy, and splitting of water into hydrogen and oxygen using light energy.

(iii) Reduction of carbon dioxide by hydrogen to form carbohydrate like glucose by utilizing the chemical energy.

(b) The opening and closing of stomata is controlled by guard cells. When water flows into the guard cells, they swell, become curved and cause the stomata to open. When the guard cells loses water, they shrink, become flacid and straight thus closing the stomata.

(c) Carbon dioxide is made available to plants when stomata are open.