Well, let me introduce you to some hormones that do just those things: the "hunger hormones," leptin and ghrelin.
Leptin is a hormone, made by fat cells, that decreases your appetite. Ghrelin is a hormone that increases appetite, and also plays a role in body weight.
Your muscules send messages to your brain through nervous system example when your injured
BIODEGRADABLE. Is what they are called
The correct answer would be "who is coming with us" assuming Jim is highschool level or younger, a chaperone should accompany them.