They vibrate in place within a fixed volume. They move around freely within a fixed volume. They vibrate in place and take the shape of a container. They move around freely and take the shape of a container.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which statement best describes the motion of the molecules of a solid object?
Possibilities:
- They vibrate in place within a fixed volume.
- They move around freely within a fixed volume.
- They vibrate in place and take the shape of a container.
- They move around freely and take the shape of a container.

They vibrate in place within a fixed volume.