You are presented with the question "what produces hormones?" and the following answer choices: 
- ferns
 - humans
 - glands
 - chemicals
 - animals
 - insects
 - Wasps
 - cows

Now knowing that thyroid hormones increase the rate of metabolism in cells throughout the body and thyroid hormones are produced by the thyroid gland, choose the best answer.


 

   glands      