Final answer:
The correct path of a naive T cell from the heart through lymphatics back to the heart is Heart → Artery → Vein → Lymphatics → Lymph nodes → Heart.
Step-by-step explanation:
The correct path of a naive T cell from the heart through lymphatics back to the heart is option c) Heart → Artery → Vein → Lymphatics → Lymph nodes → Heart.
Naive T cells are produced in the bone marrow and mature in the thymus. After maturing in the thymus, they enter the rest of the lymphatic system to search for pathogens. When a naive T cell encounters an antigen in the lymphatic system, it becomes activated and undergoes clonal expansion to fight the infection. The activated T cell then travels back to the heart through lymphatics and lymph nodes.
The lymph that enters lymph capillaries in tissues is transported through the lymphatic vessel network to two large lymphatic ducts in the upper chest, from where it flows into two major veins of the cardiovascular system.