The organ that filters water-soluble chemicals from the blood for removal in the urine.

• A. Large intestine
• B. Appendix
• C. Kidney
• D. Liver

Answer: (C)

The kidneys are the organs that filter water-soluble chemicals from the blood to remove them in urine. In the kidney’s filtering units, blood plasma is pushed into the nephron’s glomerulus, where many water-soluble substances such as wastes, salts, and certain small molecules become part of the filtrate. As the filtrate travels through the tubules, the body reabsorbs needed substances back into the blood and some wastes are secreted into the filtrate. What ultimately leaves as urine is the concentrated mix of waste and excess water.

Other organs shown are not responsible for this filtration process. The liver detoxifies and processes many compounds, but urine formation relies primarily on the kidneys. Digestive organs like the large intestine and appendix don’t filter blood into urine.