Fact 1: Thyroid hormones increase the rate of metabolism in cells throughout the body. Fact 2: Chronic stress increases thyroid hormone production. Given the two facts above, what increases the rate of metabolism in cells throughout the body?

Choose from:
(I). chronic stress;
(II). heat energy;
(III). resting up;
(IV). taking naps;
(V). smoking cigarettes;
(VI). Smoking;
(VII). sleeping well;
(VIII). sweating;
Answer:
(I).