The main purpose of the lymphatic system is to drain those substances that cannot be drained or reabsorbed by the circulatory system and returns them to the blood.

• A. True
• B. False
• C. Cannot determine
• D. Not applicable

Answer: (A)

The lymphatic system’s main job is to maintain fluid balance by collecting interstitial fluid and proteins that aren’t returned directly to the blood by the capillaries, and then returning that lymph to the venous circulation. This drainage prevents edema and helps keep circulating blood volume stable. It also supports immune function and fat absorption, but the core idea at stake here is capturing the fluid and larger molecules that the circulatory system cannot reclaim on its own and returning them to the bloodstream.

So the statement aligns with this fundamental role: it describes draining substances that the circulatory system can’t reclaim and moving them back into the blood, which is exactly what the lymphatic system does.