Which gas is essential for human respiration?

Oxygen is essential for human respiration because it is a critical component in the process of cellular respiration. During this process, cells utilize oxygen to produce energy in the form of ATP (adenosine triphosphate), which is necessary for various biological functions and maintaining life. When humans inhale, oxygen from the air enters the lungs and is then transported into the bloodstream, where it binds to hemoglobin in red blood cells and is delivered to cells throughout the body.

While nitrogen, carbon dioxide, and hydrogen are all present in the air we breathe or are involved in other biological processes, they do not play the same essential role as oxygen. Nitrogen makes up a large portion of the atmosphere but does not participate directly in the respiration process. Carbon dioxide is a byproduct of cellular respiration and is exhaled by the body; while it is important for maintaining the body’s pH balance and regulating breathing, it is not used by cells for energy production. Hydrogen, although crucial in various chemical reactions in the body, is not a gas that is utilized for respiration. Thus, oxygen stands out as the only gas that is necessary for the energy-producing processes that sustain human life.