Three states of matter are _________.

The three states of matter commonly recognized in basic science are solid, liquid, and gas. In solids, particles are arranged closely together in a fixed structure, making them rigid and maintaining a definite shape and volume. Liquids have more space between particles, allowing them to flow and take the shape of their container while retaining a definite volume. Gases consist of widely spaced particles with lots of energy, which allows them to expand and fill the entire volume of their container, leading to neither a definite shape nor volume.

While "Vapor" is related to gases, it typically refers to the gaseous state of a substance that is normally a liquid or solid at room temperature, which makes it less accurate as a primary state of matter. The inclusion of "Plasma" in other options represents a fourth state of matter, characterized by ionized gases, high energy, and electrical conduction, but this is not included in the three primary states typically taught at an introductory level. Therefore, the correct identification of the three principal states of matter is solid, liquid, and gas.