Question

what is true about the molecules in a solid?
a molecule of water is made of atoms of hydrogen and calcium.
the molecules are frozen.
the molecules of ice are vibrating in place.
rewatch

Explanation:

• The first option is incorrect: a water molecule ($H_2O$) consists of hydrogen and oxygen atoms, not calcium.
• The second option is incorrect: molecules in a solid are not "frozen" completely—they still have vibrational motion.
• The third option is correct: in solids like ice, molecules are held in a fixed structure but continuously vibrate in their fixed positions.

Answer:

C. The molecules of ice are vibrating in place.