| A | B |
| excretion | the process of removing wastes from the body |
| urea | a chemical that comes from the breakdown of proteins |
| urine | a watery fluid that contains urea and other wastes |
| ureters | two narrow tubes through which urine flows from the kidneys to the urinary bladder |
| urinary bladder | a sacklike muscular organ that stores urine |
| urethra | a tube through which urine leaves the body |
| nephron | tiny filtering factories in the kidneys that remove wastes from blood and produce urine |
| kidneys | remove urea and other wastes from the blood; the major organs of the excretory system |