Answer: Kidneys
Explanation: Your kidneys and bladder are the main parts of the urinary, or excretory, system. Your kidneys filter waste from your blood and use water, sodium, magnesium and potassium to make adjustments to your body's acid-base balance. Water is also required to help the urinary system excrete waste products.
The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help maintain internal chemical homeostasis and prevent damage to the body.
