Answer the following question: You are presented with the quiz "Thyroid hormones increase the rate of " But you don't know the answer, so you turn to your teacher to ask for hints. He says that "thyroid hormones increase the rate of metabolism in cells throughout the body" and "metabolism is the process of converting food to energy". So, what's the best answer to the question?

Choices:
1). by making heat.
2). the rest of the body.
3). female sex cells.
4). Helps them grow.
5). hydration of their cells.
6). heat produced.
7). converting food to energy.
8). aerobic capacity.
Answer:
7).