Which renal structure is responsible for producing hypertonic urine by reabsorbing water while allowing metabolic wastes and NaCl to pass through?

A. Their filtration rate: Both types of nephrons have similar filtration rates; the difference lies primarily in their structure and location.

B. Their location within the renal cortex: Cortical nephrons are located primarily in the renal cortex, while juxtamedullary nephrons are located closer to the medulla and have long loops of Henle that extend deep into the medulla.

C. The size of their renal corpuscle: The renal corpuscle size does not differ significantly between cortical and juxtamedullary nephrons.

D. Whether they drain into a collecting duct or directly into the renal pelvis: All nephrons drain into a collecting duct; none drain directly into the renal pelvis.

A. The bicarbonate, phosphate, and protein: The major chemical buffer systems in the body are the bicarbonate buffer system, the phosphate buffer system, and the protein buffer system. These buffers help maintain pH balance in the blood and other fluids.

B. The urinary and digestive: The urinary and digestive systems are involved in excretion and digestion, not buffering.

C. The bicarbonate, nucleic acids, and protein: Nucleic acids are not major buffering systems in the body; the bicarbonate, phosphate, and protein systems are the primary ones.

D. The urinary and respiratory systems play roles in regulating acid-base balance through excretion and gas exchange but are not chemical buffer systems themselves.