Which cellular waste product do the kidneys primarily remove from the blood?

• A. Glucose
• B. Bile
• C. Carbon dioxide
• D. Urea

Answer: (D)

Verified step by step guidance

1. Understand the role of the kidneys in the human body. The kidneys are responsible for filtering blood and removing waste products, maintaining electrolyte balance, and regulating blood pressure.
2. Identify the primary waste products that the kidneys filter from the blood. These include urea, creatinine, uric acid, and excess ions such as sodium and potassium.
3. Recognize that urea is a major waste product formed from the breakdown of proteins. It is produced in the liver and transported to the kidneys for excretion.
4. Differentiate urea from other substances listed in the problem. Glucose is a sugar used for energy, bile is produced by the liver to aid in digestion, and carbon dioxide is a gas expelled by the lungs.
5. Conclude that the kidneys primarily remove urea from the blood, as it is a nitrogenous waste product resulting from protein metabolism.