Photosynthesis converts energy X into energy Y.
(a) What are X and Y ?
(b) Green plants are autotrophic in their mode of nutrition. Why?

Explanation

(a) X is the light energy. Y is the chemical energy. During photosynthesis, the light energy is converted into chemical energy.
(b) Green plants are autotrophic in their mode of nutrition because they prepare their food, through a process called photosynthesis by using water, carbon dioxide, chlorophyll and sunlight.