How are the kidneys adapted for efficient exchange?

The kidneys are adapted for efficient exchange through their highly structured nephrons, which include a glomerulus for filtration and a tubule system for reabsorption and secretion. The large surface area of the renal tubules, coupled with their extensive capillary network, maximizes the absorption of water, electrolytes, and nutrients. Additionally, the permeability of the tubule walls can be adjusted to regulate the concentration of urine, facilitating precise control of fluid and electrolyte balance. These adaptations ensure that waste products are effectively excreted while essential substances are retained.