In the descending limb of the loop of Henle,as the filtrate passes downward,it:

In human kidneys,which substances are mainly responsible for creating the osmolarity gradient of the medullary interstitial fluid?

Henle's loop of nephron plays a significant role in maintaining a high osmolarity in

Select the correct option:
$(1)$ The counter-current mechanism is maintained by the Loop of Henle and the vasa recta.
$(2)$ The ascending limb of the Loop of Henle is impermeable to water.

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:

Mammals have the ability to produce