Read the following statements regarding the exchange of solutes in the counter current mechanism of the human kidney: (A) NaCl is transported by the ascending limb of Henle's loop which is exchanged with the descending limb of vasa recta. (B) NaCl is returned to the interstitium by the ascending portion of vasa recta. (C) Small amounts of urea enter the thin segment of the ascending limb of Henle's loop. (D) Urea is

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According to the NCERT description of the counter current mechanism: Statement (A) is correct: NaCl is transported by the ascending limb of Henle's loop and enters the descending limb of the vasa recta. Statement (B) is correct: This NaCl is then returned to the medullary interstitium by the ascending portion of the vasa recta, helping to build the osmotic gradient. Statement (C) is correct: Small amounts of urea diffuse into the thin segment of the ascending limb of Henle's loop from the interstitium. Statement (D