Why gases occupy entire space of the container in which they are kept?

Gases occupy the entire space of their container due to the high kinetic energy of their molecules, which move rapidly and freely in all directions. Unlike solids and liquids, gas molecules are widely spaced and experience negligible intermolecular forces, allowing them to expand and fill any available volume. This behavior is described by the principles of gas laws, which illustrate how changes in pressure, temperature, and volume affect gas behavior. As a result, gases will uniformly distribute themselves throughout the container they occupy.