What is the primary function of the lymphatic system?

The primary function of the lymphatic system is to return tissue fluid to the blood. This is crucial because the lymphatic system helps maintain fluid balance in the body by collecting excess interstitial fluid that surrounds cells and returning it to the bloodstream. This process not only prevents tissue swelling but also plays a key role in the immune system by transporting white blood cells and filtering harmful substances through lymph nodes. The lymphatic system thus ensures that fluid and immune responses are effectively managed, supporting overall health.

The other options do not accurately represent the main role of the lymphatic system. For instance, the production of hormones is primarily the function of the endocrine system, while digestion of food involves the gastrointestinal system. Regulation of body temperature is mainly managed by the integumentary system and certain other physiological processes, but is not a direct function of the lymphatic system.