What is the working subunit of kidney?

The working subunit of the kidney is the nephron. Each kidney contains about 1 million nephrons, which are responsible for filtering waste products from the blood and producing urine. The nephron consists of several parts, including the glomerulus, proximal tubule, loop of Henle, and distal tubule. The glomerulus is a small cluster of blood vessels that filters waste products from the blood. The proximal tubule reabsorbs water and nutrients from the filtrate, and the loop of Henle helps to concentrate the filtrate. The distal tubule further modifies the filtrate and helps to regulate the body's electrolyte balance.