Answer: Both processes interconvert energy from one form to another. Photosynthesis uses product of respiration (Carbon dioxide and water), while respiration uses the products of photosynthesis (glucose and oxygen).
Explanation: In photosynthesis, six molecules of water reacts with six molecules of carbon dioxide in the presence of light energy to yield one molecule of glucose and six molecules of oxygen while in respiration, six molecules of oxygen reacts with one molecule of glucose to produce six molecules of carbon dioxide, six molecules of water and energy in form of ATP.
Photosynthesis: 6H2O + 6CO2 + sunlight --> C6H12O6 + 6O2
Respiration: C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP (energy)