Waste products are constantly being produced by the body and must therefore be excreted. If they are not, they will increase in concentration and may interfere with chemical reactions or damage cells. Waste products that must be removed include carbon dioxide and urea.
“The kidneys are two bean-shaped organs that remove these toxins from your blood and produce urine to carry them from the body. This waste then trickles down the ureters — thin tubes that connect the kidneys to the bladder.” hope it helps -j (Found on google :) )