Which state of matter has a definite shape and volume?

The state of matter that has a definite shape and volume is a solid. In solids, particles are closely packed together in a fixed arrangement, which allows them to maintain a specific shape and volume. The strong intermolecular forces in solids keep the particles in place, preventing them from flowing or moving freely, which is characteristic of liquids and gases.

In contrast, liquids have a definite volume but take the shape of their container, while gases do not have a definite shape or volume and expand to fill their container. Plasma, being a state of matter consisting of ionized gases with free-moving charged particles, also does not possess a definite shape or volume. Therefore, solids are unique in having both a fixed shape and volume.