Concept:Air is not a single substance but a combination of different gases and tiny dust particles.Explanation:Air contains several gases. Nitrogen and oxygen make up most of it. Other gases like carbon dioxide, helium, ozone, argon, and hydrogen are present in smaller amounts. Tiny dust particles are also mixed in. The composition of gases varies by volume, but it is always a physical combination, not a chemical bond. Therefore, air is a mixture, not a compound or element.
