What is the primary function of the lymphatic system? 

The primary function of the lymphatic system is to help defend the body against infections and other diseases by filtering out bacteria, viruses, and other foreign substances. It also helps to maintain fluid balance by collecting and returning excess fluid, waste products, and metabolic by-products to the bloodstream. Additionally, the lymphatic system also plays a role in the immune response by producing and transporting lymphocytes and other immune cells.