Answer:
The correct option is 1) The atoms in the structure are vibrating
Explanation:
When heat is applied to an object, the atoms of the object start vibrating. As atoms vibrate faster, they break free and start to collide with one another with a much greater force. As a result, the molecules of the object expand and tend to take up more space. Hence, the correct option is 1) The atoms in the structure are vibrating.