Question

state in brief the role of photosynthesis and respiration in carbon cycle

Answer 1

Photosynthesis is performed by green plants in the presence of sunlight and it converts carbon dioxide into carbohydrates, that are utilized by other living organisms through food chain. Oxygen is replenished in nature only through the process of photosynthesis.
Respiration Oxygen enters in the living world through the process of respiration, i.e. it oxidizes the food material (glucose molecules) and produces energy and carbon dioxide.