Final answer:
Matter exists in three states: solid, liquid, and gas. Solids have a definite shape and volume, liquids have a definite volume but take the shape of the container they are in, and gases have no definite shape or volume.
Step-by-step explanation:
Matter exists in three states: solid, liquid, and gas. Solids have a definite shape and volume, while liquids have a definite volume but take the shape of the container they are in. Gases have no definite shape or volume and fill the container they are in. For example, a rock is a solid, while water is a liquid that takes the shape of its container, and air is a gas that fills its container.