Answer:
Animals and plants use oxygen for processing cellular respiration.
Step-by-step explanation:
Most of all organisms use oxygen to undergo cellular respiration with the help of the mitochondria that powers energy. Cellular respiration is needed to obtain energy for survival. As products of cellular respiration, ATP energy is created, and carbon dioxide + water is released from the organism. Thus, an ecosystem like a rainforest with animals and plants use oxygen for processing cellular respiration.