Answer:
gas is this: a substance (such as oxygen or hydrogen) that is like air and has no fixed shape. : a gas or mixture of gases that is burned as a fuel.
Step-by-step explanation:
Gas is one of the four fundamental states of matter. A pure gas may be made up of individual atoms, elemental molecules made from one type of atom, or compound molecules made from a variety of atoms. A gas mixture, such as air, contains a variety of pure gases.