What is the primary function of the lymph system?

The primary function of the lymphatic system is indeed to carry nutrients and provide immunity. The lymphatic system plays a crucial role in maintaining fluid balance within the body by collecting excess tissue fluid (lymph) and returning it to the bloodstream. In addition to this, it is integral to the immune system; it transports white blood cells and filters out pathogens, foreign substances, and cellular debris through lymph nodes. This makes the lymphatic system vital for the body's defense mechanisms and for facilitating nutrient transport, especially fats and fat-soluble vitamins absorbed from the digestive tract.

The other functions mentioned in the alternatives are attributed to different systems: the circulatory system is responsible for blood circulation, while the digestive system processes food for nutrient absorption. The endocrine system is the one that secretes hormones. Understanding the distinct roles of these systems helps clarify why the function of the lymphatic system includes both nutrient transport and immunity.