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, answer the question "What increases the rate of metabolism in cells throughout the body?" with the following options: 
- chronic stress
 - heat energy
 - resting up
 - taking naps
 - smoking cigarettes
 - Smoking
 - sleeping well
 - sweating


 

 chronic stress        