Answer:
There is a relation between both the reaction that helps in the life to sustain, the relation is that the product of the photosynthesis is the reactant in the cellular respiration which is glucose.
photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2
cellular respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O
In photosynthesis water and carbon dioxide reacts in the presence of the light energy and produces the glucose through a complex set of reaction which is stored in the body of the plant and used in cellular respiration to make energy in the form of ATP.