In materials science, what does the concept of "freedom of movement" primarily describe?

The overall temperature of a substance.

The independence of molecular motion.

The strength of the chemical bonds holding atoms together inside a molecule.

The total mass of a substance in a given volume.

A scientist observes that the molecules in a substance are tightly packed and can only vibrate in fixed positions. This low level of molecular freedom is characteristic of which state of matter?

A substance undergoing a phase change from liquid to gas.