Glucose is mostly reabsorbed by:

Correct Answer: C

Rationale: Glucose reabsorption occurs primarily in the proximal convoluted tubule (PCT). From the tubular lumen to the tubular cell, it uses secondary active transport via sodium-glucose cotransporters (SGLT), driven by the Na⁺ gradient established by Na⁺/K⁺-ATPase. From the cell to the peritubular capillary, glucose exits via facilitated diffusion (GLUT transporters), a passive process. This two-step mechanism distinguishes it from purely passive or primary active transport, making C correct.

Correct Answer: C

Rationale: Furosemide, a loop diuretic, inhibits the Na⁺/K⁺/2Cl⁻ cotransporter in the thick ascending limb of the Loop of Henle, blocking reabsorption of these ions, increasing urine output, and reducing blood volume. Thiazides (A) target the DCT, osmotic diuretics (B) work via osmolarity, and carbonic anhydrase inhibitors affect HCO₃⁻, making C correct.

Correct Answer: D

Rationale: In chronic metabolic acidosis, bone acts as an important buffer source, releasing calcium carbonate and phosphate to neutralize excess H⁺ over days to weeks, compensating when bicarbonate (C) is depleted. Phosphate (A) and proteins (B) buffer acutely but are less significant long-term, making D correct for chronic states.

Correct Answer: D

Rationale: Insulin glargine (Lantus) is a long-acting insulin with no peak, providing steady glucose control over 24 hours (D), unlike short-acting insulins. It doesn't cause weight loss (A), isn't restricted to night (B), and lasts far longer than six hours (C), making D the accurate understanding.

Correct Answer: D

Rationale: Urea is indeed formed in the liver from protein metabolism and excreted by the kidneys (D), a correct urinary system function. EPO regulates red, not white, blood cells (A), renin release occurs with low pressure/flow (B), and low creatinine suggests healthy kidneys (C), making D the accurate statement.