Answer: The excretory system.
Explanation: Excretion is a process by which an organism removes or eliminates waste products of metabolism from its body. Excretory system is a group of organs in the body to bring about the removal of waste products from the body. Every organism needs to get rid of the waste products of metabolism from its body cells because if not removed, accumulates and in high concentrations waste products becomes toxic to the body. In humans, the excretory system involves the kidney, the bladder, the urethra, the liver, lungs and skin.