One function of the lymphatic system is to conserve what?

• A. Blood cells.
• B. Fluid and plasma that leak out of capillaries.
• C. Hormones.
• D. Platelets.

Answer: (B)

Conserving interstitial fluid and returning it to the bloodstream is a key function of the lymphatic system. As plasma filters out of capillaries, some fluid remains in the interstitial space. While much is reabsorbed directly into capillaries, the rest is collected by lymphatic vessels, forming lymph, and returned to the venous system. This helps maintain blood volume and prevents tissue edema. That’s why the option describing conserving fluid and plasma that leaks out of capillaries is the best choice. The other options involve components that largely stay in the blood (blood cells and platelets) or substances carried by the blood (hormones), rather than being conserved by the lymphatic system.