The high osmolarity of the renal medulla is maintained by all of the following except

the correct option is C (diffusion of salt from the descending limb of the loop of Henle).

Explanation:

Renal medulla is the inner part of the kidney that aids in the maintenance of salt and water in the blood. High osmolarity occurs when there is much solutes example Na+, in the serum glomerular filtrates. This can be maintained by :

-the spatial arrangement of juxtamedullary nephrons.

- diffusion of salt from the thin segment of the ascending limb of the loop of Henle.

- active transport of salt from the upper region of the ascending limb.

- diffusion of urea from the collecting duct.

Note: descending limb of the loop of Henle is not permeable to salts but water.