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 :

To determine the validity of the given statements, let us analyze the physiological and anatomical features of the nephron step-by-step:

Analysis of Statement I:
The loop of Henle is a U-shaped portion of the nephron consisting of a descending limb and an ascending limb.
1. The descending limb of the loop of Henle is highly permeable to water but almost completely impermeable to electrolytes (solutes like sodium and chloride ions). As filtrate flows down this limb, water exits into the hypertonic medullary interstitium, concentrating the urine.
2. In contrast, the ascending limb of the loop of Henle is impermeable to water but permeable to electrolytes (either actively or passively).
Therefore, Statement I, which claims that the descending limb is impermeable to water and permeable to electrolytes, is false.

Analysis of Statement II:
The proximal convoluted tubule (PCT) is a major site of reabsorption in the nephron.
1. The PCT is lined by simple cuboidal brush border epithelium, not simple columnar epithelium.
2. The presence of microvilli (forming the "brush border") indeed increases the surface area significantly to facilitate maximum reabsorption of water, essential nutrients, and electrolytes.
Because the cell type is cuboidal rather than columnar, Statement II is false.

Conclusion:
Since both Statement I and Statement II are incorrect, the correct option is that both Statement I and Statement II are false.