Answer:
Oxygen
Explanation
Cellular respiration means taking Oxygen and using it to "breathe" and also be used in many other processes.
Answer:
Photosynthesis is the process where green plants synthesis energy using the energy of the sun, carbon dioxide and water. Photosynthesis is very important to life it keeps most plants alive (autotrophs), and heterotrophs eat autotrophs to help them het energy. An autotroph is an organism that synthesis its own energy and heterotroph is an organism that gets it energy by digesting other organisms.
