Which of the following are the three states of matter?

The three states of matter are indeed solid, liquid, and gas. This classification is fundamental in the study of physical science and reflects the different ways in which substances can exist and behave under various conditions.

In a solid state, particles are closely packed together and vibrate in place, which gives solids a definite shape and volume. In a liquid state, particles are still close together but can move past one another, allowing liquids to flow and take the shape of their container while maintaining a fixed volume. In a gas state, particles are far apart and move freely, filling the entire volume of their container and allowing gases to expand and compress easily.

The other options present variations of states that either include states not commonly recognized as primary (such as plasma or vapor) or introduce terms that do not refer to states of matter in this context (like mass). Plasma is indeed a state of matter, but it is not one of the three basic states traditionally taught, and vapor is a gaseous state under specific conditions rather than a separate state itself. Mass, on the other hand, is a measure of the amount of matter in an object, not a state of matter. Understanding these distinctions is crucial for grasping the concepts of matter in physical science.