For this question use the main assumptions of the kinetic molecular theory of gases:
1. gases are made up of molecules which are relatively far apart.
2. the molecules are in motion at high speeds.
3. the molecular collisions are perfectly elastic.
4. increase in temperature increases the kinetic energy of the molecules.
which of the above assumptions accounts for the compressibility of gases as compared to liquids and solids?

The correct answer is 3. The molecular collisions are perfectly elastic.

Explanation:

The kinetic theory of gases explains the characteristics and properties of matter in general, and establishes that heat and movement are related. This theory tells us that a gas is composed of a large number of small particles (molecules) of negligible size compared to the distances between them. The theory also indicates that the molecules of a gas are kept in continuous motion in a rectilinear, fast and random (random) way in all directions, colliding with each other and with the walls of the container that contains it in elastic shocks (that is, there is no force of attraction or repulsion between the molecules, nor between them and the container, different from those of the shock).  Finally, each molecule has its own kinetic energy (velocity) that is not necessarily equal to the rest of the molecules. But the average kinetic energy of all particles is proportional to the absolute temperature of the gas. Temperature is a consequence of molecular movement.

Taking into account everything mentioned above, it is possible to say that the correct answer is 3. The molecular collisions are perfectly elastic.