The lymphatic system primarily supports which functions?

• A. To move air into the lungs
• B. To support immune function and fluid balance
• C. To transport nutrients to cells
• D. To regulate heart rate

Answer: (B)

The lymphatic system primarily supports immune defense and tissue fluid balance. It collects excess interstitial fluid from tissues and returns it to the bloodstream, helping prevent edema and maintain circulating blood volume. It also houses and transports immune cells; lymph nodes filter pathogens, and organs like the spleen and thymus play key roles in mounting immune responses. Additionally, fats absorbed from the digestive tract are carried by lymphatic vessels (lacteals), linking to nutrient handling, but the central function is immune surveillance and fluid balance. The other options align with different systems: moving air is a respiratory function, regulating heart rate is controlled by the nervous/cardiovascular systems, and delivering nutrients to cells is primarily the job of the circulatory system.