What are the three fundamental states of matter?

The three fundamental states of matter are solid, liquid, and gas. These states are defined by the arrangement of particles and the energy they possess. In solids, particles are closely packed in a fixed arrangement, which gives solids a definite shape and volume. In liquids, the particles are still close together but can move past each other, allowing liquids to take the shape of their container while maintaining a fixed volume. In gases, the particles are much farther apart and move freely, causing the gas to expand and fill the entire volume of its container.

While other choices mention variations or different phases of matter, they do not accurately reflect the three fundamental states as recognized in classical physics and chemistry. Plasma, for example, is a state of matter similar to gas but consists of charged particles and is found in stars, including the sun. Vapor refers to the gaseous form of a substance that is typically liquid at room temperature, making it a phase rather than one of the fundamental states. Foam is a colloidal system, which consists of a gas dispersed in a liquid or solid, and it does not represent a fundamental state of matter. Thus, the fundamental states that encapsulate all forms of ordinary matter at a macroscopic level are indeed solid, liquid, and gas