Answer:
The product of one process is the reactant of the other and vice versa.
Explanation:
Photosynthesis is a process whereby autotrophs e.g. plants make their own food in form of organic molecule (glucose) by combining the carbondioxide (CO2) they absorb via their stomata and water (H2O) using the energy they obtain from sunlight.
Photosynthesis uses C02 and H2O as starting materials and produce glucose and 02 as products.
6CO2 + 6H2O ------> C6H12O6 + 6O2
On the other hand, organisms including this photosynthetic organisms need energy for their life processes. They obtain this energy by breaking down energy-containing organic molecules (glucose) to produce energy usable by their cells (ATP). This process is called CELLULAR RESPIRATION. Cellular respiration can occur in the presence of oxygen (aerobic) or absence of oxygen (anaerobic). The aerobic cellular respiration is depicted as follows:
C6H12O6 + 602 -----> 6CO2 + 6H2O
Aerobic cellular respiration uses glucose and oxygen as a starting material and produces C02 and water as products.
Due to this connection between photosynthesis and respiration, they are regarded as direct opposite of each other.