GED Science Practice

Oxygen is a nonmetallic bivalent element that exists as a colorless, odorless, tasteless, and nonflammable diatomic gas under standard temperature and pressure conditions. In its diatomic form (O2), it plays a crucial role in supporting life as it is essential for respiration in many organisms. Oxygen makes up about 21% of Earth's atmosphere and is vital for processes such as combustion and cellular respiration. The other options are not correct in this context. Ozone is a triatomic molecule (O3) and has a distinct odor and color. Penicillin is an antibiotic derived from fungi, not an element. A pathogen refers to any microorganism that can cause disease and is not a specific element or compound.