Answer:
The photosynthesis chemical reaction looks like this:
6 CO₂ + 6 H₂O --> C₆H₁₂O₆ + 6 O₂
The cellular respiration chemical reaction looks like this:
C₆H₁₂O₆ + 6 O₂ --> 6 CO₂ + 6 H₂O
As you can see, the processes involve the same substances. However, the reactants and the products are switched. The reactants for photosynthesis are the products for cellular respiration, and vice versa. For example, the products of photosynthesis are glucose (C₆H₁₂O₆) and oxygen. On the other hand, these are the reactants necessary for cellular respiration.