Final answer:
The property not considered a characteristic of a gas is 'D. Particles.' While gases are composed of particles, 'particles' is not a standalone property but an aspect of gas behavior explained by other properties such as pressure, volume, and temperature.
Step-by-step explanation:
The characteristic or property that is not considered a characteristic of a gas is D. Particles. When discussing the physical properties of gases, we focus on aspects such as pressure, volume, temperature, and amount of gas. These properties are essential to understanding gas behavior according to the kinetic molecular theory (KMT), which states that gas particles have enough kinetic energy to break free from intermolecular forces and move about randomly within a container. Gases are known for their ability to compress and expand to fill the volume of their container, their low density, and the fact that their behavior does not depend on the chemical identity of the gas particles. As such, 'particles' as a term is not a standalone characteristic describing a property of a gas, but rather is understood as part of the overall behavior of gases.