Evidence that a gas consists mostly of empty space is the fact that: (A) the density of a gas becomes much greater when it is liquefied (B) gases exert pressure on the walls of their containers (C) gases are transparent (D) heating a gas increases the molecular motion (E) nature abhors a vacuum

(A) the density of a gas becomes much greater when it is liquefied

Explanation:

The gaseous state is composed of mainly empty space, therefore, the density of the gas increases as it goes to the liquid phase.

As, in the liquid state, the molecules are close together, there by increasing the density of the liquid state.

There fore, from the options, the most appropriate is option a.