Coordinating body functions via chemical signals is accomplished by

The correct answer is: Endocrine system.

Explanation:

The Endocrine system is comprised of a number of glands which synthesize and secrete bio-chemical signals directly into the blood stream. These bio-chemical signals are made of peptides, proteins or steroids and are called Hormones. These hormones act on the target organs or tissues which are usually located far away from the site of production or synthesis of the hormone. They can act on only those organs which have the receptors capable of recognizing the hormone. They are responsible for regulating growth, development, metabolism, reproduction, sleep and other short and long term activities in the body. Their production and synthesis is highly regulated and small quantities of these chemical messages are capable of bringing about drastic response in the cells, tissue, organs or the whole body.