Final answer:
The proximal tubule has a leakier epithelium and a larger apical surface area compared to the distal tubule. The larger surface area results from a brush border of microvilli, and the leakier epithelium aids in effective reabsorption. Option number 1 is correct.
Step-by-step explanation:
In comparison to the distal tubule, the proximal tubule has a leakier epithelium and a larger apical surface area. This is observed in the structure of the proximal convoluted tubule (PCT), which is made up of simple cuboidal cells with prominent microvilli known as a brush border. The brush border significantly increases the apical surface area, enhancing the PCT's ability to absorb and secrete solutes effectively.
Additionally, the PCT's leakier membrane facilitates the reabsorption of water and solutes into the bloodstream. This differs from the distal convoluted tubule (DCT), which has a tighter epithelium and fewer microvilli on its apical surface, reflecting its role in selectively secreting and absorbing ions to maintain blood pH and electrolyte balance, and its response to hormones such as aldosterone which increases Na+/K+ ATPase levels in the basal membrane.