D) cell respiration
Photosynthesis is the primary funtion of the leaves.
Step-by-step explanation:
Photosynthesis is defined as the chemical process of converting light energy into chemical energy in a form of food or sugar. Leaves contain most of the chloroplasts in plants that are responsible in capturing light for photosynthesis to occur.
Leaves are naturally green to serve their purpose. This green color is caused by the reflection of the green portion of the visible light spectrum by the green coloring pigment, chlorophyll. Chlorophyll, that is contained in chloroplasts, captures certain wavelengths of light, as energy to initiate photosynthesis. As a result, we get food from plants.