Q. Which one of the following is not the excretory organ?
Answer: Spleen
Notes: The excretory system is a collection of organs tasked with removing excess nitrogen and other toxins from the body. Several parts of the body such as sweat glands (excretion of sweat), liver (detoxifies and breaks down chemicals, poisons and other toxins that enter the body), lungs (disposal of carbon dioxide through exhalation) and kidneys (excretion of waste through urinary system) are involved in this process. The spleen also called grave yard of RBC is not considered as an excretory organ.