A gas has no definite shape and no definite what?

A gas has no definite volume. In contrast to solids, which have a fixed shape and volume, and liquids, which have a definite volume but no fixed shape, gases expand to fill the entire space of their container. This means the particles in a gas are far apart and move freely, allowing the gas to occupy whatever volume is available. Gases can be compressed, and their volume can change depending on the pressure and temperature of the environment they are in. Hence, understanding that gases do not have a definite volume is fundamental to grasping the differences among states of matter.