What is the chemical produced by the body to control
body functions such as growth and
reproduction?

The chemical produced by the body to control such as growth and reproduction is called hormones. It is secreted through Endocrine gland

Explanation:

The main role of hormone is to communicate with body. it releases through blood stream. it also creates change in those cells which is near of its surrounding tissue. it works with nervous and immune system. It helps our body cope with different events and stresses.

It controls blood sugar in our body. The main role of this gland is "growth, repair and reproduction". it also includes development of brain

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

that is true   : ) hope this you