What is osmoregulation and give an example.

• A. Regulation of water content only in aquatic environments.
• B. Regulation of body temperature to maintain homeostasis.
• C. Regulation of pH in the blood.
• D. Regulation of water and solute balance; examples include kidney regulation in animals and stomatal control in plants.

Answer: (D)

Osmoregulation is the regulation of water and dissolved substances to keep body fluids at the right concentration and volume, so cells function properly and metabolic processes proceed smoothly. This involves controlling both how much water is retained or lost and how solutes are managed. In animals, the kidney adjusts urine concentration and volume to maintain fluid balance. In plants, mechanisms like stomatal opening and closing regulate water loss while allowing gas exchange, contributing to overall water balance. Other options describe different regulatory goals—temperature control, pH balance, or water content in only aquatic settings—so they don’t capture the full idea of osmoregulation as balancing water and solutes across organisms.