Air is a

Correct answer: (c) mixture

Explanation

Air is a mixture, not a compound: its gases are not chemically combined, keep their own properties and are present in varying amounts.

By volume, dry air is about 78% nitrogen, 21% oxygen, 0.93% argon and 0.04% carbon dioxide, with traces of neon, helium, methane, krypton and hydrogen. Its parts can be separated by fractional distillation of liquid air.