The oven's interior reflects heat onto the food. The oven's interior, like a lens, focuses heat onto the food. Water molecules in the food reflect energy from microwave radiation. Water molecules in the food absorb the energy of microwave radiation.
I gave my students this multiple choice question: Which of the following describes how a microwave oven heats food?

Only one answer is correct among these 4 choices:
- The oven's interior reflects heat onto the food.
- The oven's interior, like a lens, focuses heat onto the food.
- Water molecules in the food reflect energy from microwave radiation.
- Water molecules in the food absorb the energy of microwave radiation.

Could you tell me which one is correct?

Water molecules in the food absorb the energy of microwave radiation.