Which of the following factors is responsible for the formation of concentrated urine?

Which of the following diagrams is correct with regard to the proximal $(P)$ and distal (D) tubule of the Nephron.

Choose the correct statement given below regarding juxta medullary nephron.

Given below are two statements : Statement I : In the nephron, the descending limb of loop of Henle is impermeable to water and permeable to electrolytes. Statement II : The proximal convoluted tubule is lined by simple columnar brush border epithelium and increases the surface area for reabsorption. In the light of the above statements, choose the correct answer from the option given below :

Given below are two statements: Statements I: Concentrated urine is formed due to counter current mechanism in nephron. Statement II: Counter current mechanism helps to maintain osmotic gradient in the medullary interstitium. In the light of the above statements, choose the most appropriate answer from the options given below.

Diuresis is prevented by: