A sample of a gas is contained in a closed rigid cylinder. According to the kinetic molecular theory, what occurs when the gas inside the cylinder is heated and the temperature increases?

A.
The average kinetic energy of the gas molecules increases.
B.
The number of gas molecules increases.
C.
The volume of the gas decreases.
D.
The number of collisions between gas molecules decreases.

A. The average kinetic energy of the gas molecules increases.