What theory explains states of matter through the motion of tiny particles?

The kinetic theory is the correct choice as it specifically explains the states of matter—solid, liquid, and gas—through the motion and behavior of tiny particles, such as atoms and molecules. According to this theory, all matter is composed of small particles that are in constant motion. The energy and speed of these particles dictate the physical state of the matter. In solids, particles are closely packed together and vibrate in place, leading to a fixed shape. In liquids, particles are still close but can move past one another, allowing the liquid to take the shape of its container. In gases, particles are far apart and move freely, resulting in no fixed shape or volume.

This foundational concept allows us to understand how changes in temperature and pressure can influence the state of matter. For instance, heating a solid increases the kinetic energy of its particles, potentially leading to a transition to a liquid state when the energy is sufficient to overcome intermolecular forces.

The other theories listed—chemical theory, nuclear theory, and relativity theory—do not specifically address the motion of particles in relation to states of matter. Chemical theory deals more with chemical reactions and properties of substances, nuclear theory focuses on the components and interactions within an atomic nucleus, and relativity theory primarily