Oxygen exchange is the process by which oxygen is taken in and carbon dioxide is released by living organisms. In humans and many animals, this occurs in the lungs, where oxygen from the air enters the bloodstream, and carbon dioxide, a waste product, is expelled. This exchange is vital for cellular respiration, which provides energy for bodily functions. In plants, oxygen exchange happens during photosynthesis. Plants absorb carbon dioxide from the air and, using sunlight, convert it into glucose and oxygen. The oxygen is then released back into the atmosphere, contributing to the air we breathe and supporting life on Earth.