What are the three states in which matter can exist?

The three fundamental states in which matter can exist are solid, liquid, and gas. In the solid state, particles are closely packed together, giving solids a fixed shape and volume. In liquids, particles are still close but can flow past each other, allowing liquids to take the shape of their container while maintaining a fixed volume. Gases consist of widely spaced particles that move freely, filling the volume of their container and taking its shape.

While other states like plasma do exist, they are typically considered more specialized states that occur under specific conditions, such as high temperatures or energy levels. Therefore, the correct grouping of the most common states of matter—covering the general behavior and properties of substances at various conditions—is solid, liquid, and gas.