What are the three states of matter?

The three commonly recognized states of matter are solid, liquid, and gas. In solids, particles are closely packed together in a fixed structure, which gives them a definite shape and volume. Liquids have a definite volume but take the shape of their container, as the particles are less tightly packed, allowing them to flow. Gases, on the other hand, have neither a definite shape nor volume; they expand to fill the entire space available to them, with particles that are far apart and move freely.

This foundational concept is key in understanding matter's behavior under different conditions. While plasma is indeed a state of matter, it is not as universally acknowledged as the first three; hence the options that include plasma are not aligned with the basic definitions taught within introductory physics. Similarly, the combinations of ‘vapor’ and ‘crystal’ present in other answer choices do not accurately represent the three fundamental states recognized in most physical science curricula.