Humans have two kidneys and each kidney is supplied with blood from the renal artery. The kidneys remove from the blood the nitrogenous wastes such as urea, as well as salts and excess water, and excrete them in the form of urine
Poop. I don't really know what you are asking but the excretory system removes the stuff from our stomach that we cant use or stuff that already has all of the nutrients that we need removed. Hope this helps
