Answer: The answer is: The collisions of particles with one another are completely elastic.
Step-by-step explanation:
The kinetic molecular theory assumes that the gas particles move in a straight line until they collide with another gas particle or with the walls of the container. Collisions are considered perfectly elastic which means that no energy is lost during these collisions. Other assumptions also suggest that the size of the gas particles is negligible compared to the total volume occupied by the gas and that the average kinetic energy of the particles is proportional to the temperature.