C. Liquid molecules and atoms are able to slip around each other and fill in gaps between them.
Explanation:
The liquid is a state of matter that has no definite shape. In fact, it can adapt to the shape of its container. This is because of the reason that molecules in the liquid phase have high kinetic energy and weak binding forces. The high energy keeps them moving freely and thus can take the shape of it its container. On the other hand, in solids, the binding forces are stronger and molecules have very little energy to move freely.
Example: If we melt a solid, the molecules initially have less energy. However, when we heat them, they gain energy and start moving. Upon further heating, they will have enough energy to break the bondings and move around. This is why the solid structure will change to the liquid.
