Which system regulates and controls growth development and metabolism?

The system that regulates and controls growth, development and metabolism is called the endocrine system. The system also regulates tissue function, sleep, mood, and sexual function among other things. 

System which regulates and controls growth development and metabolism is Endocrine system. This system completes its tasks through a network of glands, which are small but very important organs that generate, store, and secrete hormones. It secrete hormones directly into the bloodstream internally.
I hope it helped.

I’d say a : water molecules