THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Water is the most abundant molecule in a cell. Although the plasma membrane separates the interior of the cell from its extracellular environment, specialized membrane channels facilitate water transport across these biomembranes. Such water channels, which are in the form of proteins, are called aquaporins.

Detailed explanation-2: -Aquaporin-1 is extremely abundant in the proximal convoluted tubule and descending thin limb, but is notably absent in highly water-impermeable segments such as the ascending thin limb, thick ascending limb, and distal tubule.

Detailed explanation-3: -The primary function of most aquaporins is to transport water across cell membranes in response to osmotic gradients created by active solute transport.