Which of the following statements correctly represent assumptions or direct consequences of the kinetic theory model of an ideal gas?

I. The duration of a collision between a gas molecule and the container wall is negligible compared to the average time elapsed between collisions. II. The mean translational kinetic energy of the molecules is directly proportional to the temperature of the gas measured in degrees Celsius (${}^{\circ }C$). III. Because intermolecular forces of attraction are negligible except during collisions, the internal energy of an ideal gas consists entirely of the random kinetic energy of its molecules.