Which of the following could be a definition of a hormone?

Q. Which of the following could be a definition of a hormone?

A.            chemicals released to communicate between adjacent cells in contact.

B.            a chemical messenger released into blood to coordinate activities in distant tissues.

C.            a chemical messenger released by a neurone at a synapse.

D.            a chemical messenger in the extracellular fl uid between cells of a single tissue.

Answer: a chemical messenger released into blood to coordinate activities in distant tissues.