I belive they are to grow, repair, and reproduce.
Http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072434/
There is a website with some info. Hope it helps! :)
The effect of such toxic chemicals to the body is that they stimulate uncontrolled cell division. Uncontrolled cell division or cells proliferation may lead to cancer. The unchecked cell growth results to mutations in genes that can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death.
The role is that it helps you with the urinal system and makes the things in your body go out of the body. (hopes it at least helped a little! (=^T^=)
Sweating because sweating releases excess heat from the body.
