The process by which animals and humans breathe is known as respiration. This physiological mechanism involves the exchange of gases, primarily oxygen and carbon dioxide, between the body and the environment. In humans, this occurs through inhalation, where oxygen enters the lungs, and then oxygen diffuses into the bloodstream to supply cells. At the same time, carbon dioxide, a waste product generated from cellular metabolism, is expelled through exhalation. Respiration is vital for sustaining life and energy production, supporting various biological functions and processes, including metabolism, growth, and cellular repairs.