Q: You are presented with the quiz "What is the process of breaking down food proteins into energy or heat?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "digestion is the process of breaking down food into components the body can absorb" and "food proteins are changed into energy or heat to be used or absorbed by the body". So, what's the best answer to the question?

Select from the following. 1. dissecting. 2. dehydration. 3. elimination. 4. energy. 5. digestion. 6. Cooking. 7. calorie retention. 8. Evaporation.
The answer is:
5.