O2 (Molecular Oxygen)

O2, or molecular oxygen, is a colorless, odorless gas essential for life on Earth. It comprises two oxygen atoms bonded together and makes up about 21% of the Earth's atmosphere. Plants produce O2 through photosynthesis, which humans and animals rely on to breathe. O2 supports combustion, enabling fires and energy production. It's crucial for cellular respiration, where cells use oxygen to convert food into energy. In summary, O2 is vital for living organisms, fueling life processes and maintaining environmental balance.