Final answer:
Gases are characterized by their ability to expand to fill containers, high compressibility, and extremely low densities. These properties are due to the motion and spacing of the gas particles, and how they interact with one another and their environment.
Step-by-step explanation:
The question pertains to the properties of gases. Gases differ from liquids and solids in that they have unique characteristics: a) Gases expand to fill their containers, taking the shape and volume of the space they are in. This is because gases consist of tiny particles that are in constant motion and far apart from each other, leading to gases having no definite shape or volume. b) They are also highly compressible since the particles are spread out and can be brought closer together with pressure, which relates to their large coefficients of volume expansion. c) Gases have extremely low densities compared to solids and liquids because most of the space in a gas is empty and the particles are less mass per unit volume.
Moreover, gases exhibit similar expansion rates with temperature changes that are generally the same for all gases (ß), differing from how liquids and solids behave. Lastly, gas particles undergo elastic collisions with both each other and the container walls, maintaining a constant level of kinetic energy and ensuring gases mix together spontaneously.