Which statement correctly completes the kidney function sentence?

• A. Removal of: glucose, amino acids, vitamins; regulate hormones, blood pressure, temperature
• B. Removal of: ammonia, bilirubin, cholesterol; regulate digestion, respiration, circadian rhythm
• C. Removal of: potassium, sodium, chloride; regulate iron, calcium, magnesium
• D. Removal of: creatinine, urea, uric acid; regulate fluid, acid-base, electrolytes

Answer: (D)

Kidneys remove waste products from the blood while also keeping fluid balance, acid-base balance, and electrolytes on an even keel. The wastes creatinine, urea, and uric acid come from normal metabolism and are excreted in urine, so describing removal of these wastes directly reflects kidney function. At the same time, the kidneys regulate fluid volume, maintain pH by adjusting hydrogen ion and bicarbonate handling, and manage electrolytes such as sodium, potassium, and chloride. The other statements mix in functions not primarily handled by the kidneys—such as waste products from the liver or gut, temperature regulation, or regulation of minerals in a way that doesn’t match typical kidney roles. Therefore, the description of removing creatinine, urea, and uric acid and regulating fluid, acid-base, and electrolytes best matches kidney function.