The main function of lymphatic circulation is to A. transport hormones around the body. B. provide immune functions for protection. C. provide a backup for systemic circulation. D. transport nutrients and oxygen to cells. Solution Answer: B. provide immune functions for protection. The lymphatic system is an essential part of the circulatory (also known as cardio vascular) system and also plays a crucial part in the immune system. It comprises a network of lymphatic vessels that are responsible removing the interstitial fluid from around the tissues and bring it back to circulation. It also is responsible for carrying the dendritic cells and white blood cells to the lymph nodes (where they basically trigger an immune response)..