The element essential for human respiration is oxygen. Oxygen is a colorless, odorless gas that is vital for the survival of most living organisms. It constitutes about 21% of Earth's atmosphere and plays a crucial role in cellular respiration, a process by which cells extract energy from nutrients. During respiration, organisms inhale oxygen, which travels to the bloodstream and is utilized by cells to produce adenosine triphosphate (ATP), the energy currency of the cell. Depriving the body of oxygen can lead to serious health consequences, as it is fundamental for maintaining metabolic processes and supporting life.