Q.

Which of the following statements is correct                 [2017]

1 The descending limb of loop of Henle is impermeable to water.  
2 The ascending limb of loop of Henle is permeable to water.  
3 The descending limb of loop of Henle is permeable to electrolytes.  
4 The ascending limb of loop of Henle is impermeable to water.  

Ans.

(4)

Descending limb of loop of Henle is permeable to water but almost impermeable to electrolytes. Ascending limb of loop of Henle is impermeable to water but permeable to electrolytes.