Vasa recta refers to . . . . . . .

Which structures take part in the counter-current mechanism?

Human urine as compared to human blood is

Which of the following statements about the reabsorption process in Henle's loop are correct?
$(a)$ The descending limb of Henle's loop is permeable to water but almost impermeable to electrolytes.
$(b)$ Urine gets concentrated in Henle's loop.
$(c)$ Reabsorption of $Na^+$ and water takes place in Henle's loop.
$(d)$ Active or passive transport of electrolytes occurs in the ascending limb of Henle's loop.
Choose the correct answer from the options given below:

Describe the counter-current mechanism.

If $Henle's$ loop were absent from the mammalian nephron,which of the following is to be expected?