What does the following figure represent?

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

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:

Vasa recta refers to . . . . . . .

Given below are two statements with respect to counter current mechanism.
$Statement-I$: Tissue fluid around the descending limb of Henle's loop becomes concentrated, during the counter current mechanism.
$Statement-II$: Water moves out from the descending limb of Henle's loop into the tissue fluid by osmosis.
In the light of the above statements, select the correct option from the codes given below:

$A$: The final reabsorption of water from urine into blood occurs through the collecting duct of a mammalian nephron,resulting in the production of hyperosmotic urine.
$R$: The loop of Henle is responsible for the formation of a sodium gradient across the depth of the medullary interstitium of a mammalian kidney.