Answer:
Oxygen
Step-by-step explanation:
Photosynthesis is a process performed by the plants (also some algae and bacteria) in which the energy of sunlight is transformed into chemical energy usable by those plants. Necessary components of this set of reactions are sunlight, water and CO2, while resulting products are glucose and oxygen. Products of photosynthesis are then used in the metabolic processes known as cellular respiration. During the cellular respiration, glucose and oxygen are used for the production of ATP, CO2 and water. Cellular respiration is performed in all living organisms.