Which gas is primarily exhaled from the body during respiration?

During respiration, the primary gas that is exhaled from the body is carbon dioxide. This process is crucial for maintaining the body’s pH balance and removing metabolic waste. When cells perform metabolic functions, they consume oxygen to produce energy and, as a byproduct, generate carbon dioxide. This carbon dioxide is then transported in the bloodstream to the lungs, where it is expelled from the body during the exhalation phase of respiration.

Oxygen is inhaled during respiration but is not the main gas expelled; instead, it is used by the body. Similarly, nitrogen is present in the air we breathe but it does not significantly change during gas exchange in the body, as it is generally inert and not utilized in metabolic processes. Hydrogen, while it plays roles in various biochemical reactions, is not a significant component of exhaled gases in normal respiratory function. Thus, carbon dioxide is identified as the primary waste product of respiration that is exhaled.