Here's why:
* Abundance: Oxygen makes up about 65% of the mass of a human body, making it the most abundant element by far.
* Key role in water: Water (H₂O) is essential for life, and oxygen is a major component of water molecules.
* Cellular respiration: Oxygen is crucial for cellular respiration, the process by which cells convert food into energy.
* Organic molecules: Oxygen is a component of many organic molecules, including carbohydrates, lipids, proteins, and nucleic acids.
While other elements are also important for life, oxygen's prevalence and vital role in essential biological processes make it the most dominant element in living organisms.
