<prompt> A 78-year-old man is brought to the hospital because of persistent nausea and vomiting. On examination he appears dry, his abdomen is soft, and the JVP is not visible. Laboratory investigations reveal hypernatremia 158 mEqL and his calculated free water deficit is approximately 3 L. What segment of the normal kidney is most of the water reabsorbed from?collecting ductsproximal tubuledistal tubuleascending loop of Henle  <response>: The largest volume of water is reabsorbed in the nephron at the proximal convolution. Maximally concentrated urine depends on ADH, which allows distal convoluted tubes and collecting ducts to become permeable to water. 