What effect does aldosterone have on the kidneys?

Aldosterone is a steroid hormone produced by the adrenal glands, and it plays a crucial role in regulating sodium and potassium levels in the body. Its primary function in the kidneys is to increase the reabsorption of sodium and water, while promoting the excretion of potassium. When aldosterone is secreted, it acts on the distal convoluted tubules and collecting ducts of the nephrons, the functional units of the kidneys.

By increasing the reabsorption of sodium, aldosterone leads to water being reabsorbed passively due to osmotic forces, which raises blood volume and blood pressure. This mechanism is essential for maintaining fluid balance and electrolyte homeostasis in the body. Therefore, the correct answer reflects the role of aldosterone in enhancing the reabsorption of both water and salt in the kidneys, supporting key physiological processes.