Which pair of organs filter blood to produce urine?

• A. Liver
• B. Kidney
• C. Lungs
• D. Spleen

Answer: (B)

Filtering blood to make urine is the function of the kidneys. Each kidney contains many nephrons that filter blood to form a filtrate. As this filtrate moves through the renal tubules, water and essential solutes are reabsorbed while wastes and excess ions are secreted into the filtrate, concentrating it into urine that’s eventually excreted. This process helps regulate fluid balance, electrolyte levels, and waste removal from the body. Other organs have different roles: the liver processes nutrients and detoxifies substances, the lungs exchange gases and help control pH, and the spleen filters blood for immune function. Because only the kidneys are directly responsible for producing urine from filtered blood, they are the organs described.