Photosynthesis converts energy X into energy Y.

a) What are X and Y?

b) Green plants are autotrophic in their mode of nutrition. Why?

a. X is light energy and Y is chemical energy.

The sunlight energy is trapped by chlorophyll and is used in photosynthesis process. By using raw materials carbon dioxide and water in presence of light energy, glucose and oxygen are produced. The whole process occurs in chloroplasts. Glucose is a chemical compound so light energy is converted into chemical energy.

b. Plants can prepare their own food, they do not depend upon others for food. They have chlorophyll pigment which can trap sunlight energy and by using carbon dioxide and water they produce glucose. So they are autotrophic in nature.