ANATOMY

Detailed explanation-1: -Most of the fluid that is filtered at the glomerulus is then reabsorbed in the proximal tubule and the descending limb of the loop of Henle. AQP1, which is expressed in the apical and basolateral segment of the renal tubular epithelial cell plasma membrane, is primarily responsible for this water transport.

Detailed explanation-2: -Most of the solute reabsorbed in the proximal tubule is in the form of sodium bicarbonate and sodium chloride, and about 70% of the sodium reabsorption occurs here.

Detailed explanation-3: -The proximal convoluted tubule (PCT) is a segment of the renal tubule responsible for the reabsorption and secretion of various solutes and water. The PCT is located in the renal cortex, the outer part of the kidney, and is the first segment of the renal tubule, where it receives the filtrate from the renal corpuscle.

Detailed explanation-4: -Answer and Explanation: The part of a nephron in which most reabsorption occurs is (b) proximal convoluted tubule.