What is the unit of the excretory system?

A Nephron is the basic functional unit of the kidney, responsible for filtering waste products from the blood and reabsorbing substances. 

It is made up of two parts: a renal corpuscle, which filters the blood, and a renal tubule, which reabsorbs useful substances and excretes waste. 

The Nephron is responsible for maintaining fluid and electrolyte balance in the body, as well as regulating blood pressure and producing hormones such as erythropoietin and renin. 

Each kidney contains approximately 1 million nephrons that collaborate to perform the excretory system's vital functions.