The kidneys in humans are part of system that performs one of the following functions.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Excretion
The kidneys belong to the excretory system. They filter the blood in their nephrons, reabsorb what the body needs, and pass out the nitrogenous waste — chiefly urea — along with excess salts and water as urine.
In doing so they also keep the water and salt balance of the body steady. Nutrition is the work of the digestive system, transport of the circulatory system, and respiration of the lungs.