Reabsorption of water is the main function of?

Reabsorption of water is the main function of the kidneys, specifically within the nephrons. The loop of Henle, distal convoluted tubule, and collecting ducts play critical roles in this process, allowing the body to conserve water and maintain fluid balance. Hormones such as antidiuretic hormone (ADH) regulate the permeability of these structures to water, facilitating reabsorption based on the body's needs. Thus, the kidneys are essential for homeostasis regarding water levels.