02 (O2)

Oxygen (O₂) is a colorless, odorless gas essential for most life on Earth. It makes up about 21% of the air we breathe. Our bodies use oxygen to produce energy by allowing cells to convert nutrients into fuel. Without enough oxygen, organs and tissues can't function properly, which can lead to fatigue, confusion, or more serious health issues. Oxygen is also vital for combustion, helping fires burn, and is used in medical treatments to support patients breathing or recover from surgery. It’s a fundamental element for life and many industrial processes.