Humans inhale oxygen, a gas essential for survival. Oxygen is crucial for cellular respiration, a process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. The body requires a steady supply of oxygen to sustain organ function and maintain overall health. Oxygen also supports the production of ATP (adenosine triphosphate), which powers most cellular activities. While we also breathe in nitrogen, it is oxygen that is vital in maintaining life. Without it, the body's cells would become unable to function, leading to severe health issues and eventually death.