Achemical that, in relatively small amounts, produces injury when it comes in contact with skin tissue is known as:

That's  a project for you to do. btw your teacher probably uses a plagiarism detector and if you do copy anything on this site she/ he will find out and instead of getting a good  or bad grade you'll  get a 0 no exceptions, and they'll  probably call ur parents. so do some research ask friends and fam to you.

Answer(d) they all send signals from the brain to the body through long axons in the vertebral column;