Which of the following refer to passive immunity? (select all that apply)

A. GALT (Gut-Associated Lymphoid Tissue) refers to lymphoid tissue found in the gastrointestinal tract, not a part of the lymph node.
B. The hilum is the indented area of a lymph node where blood vessels, nerves, and efferent lymphatic vessels (which carry lymph out of the node) exit the node.
C. Buboes are swollen lymph nodes, often a sign of infection like bubonic plague, not the area where vessels exit the lymph node.
D. Filariae are parasitic worms that can cause lymphatic filariasis, but they are not related to the structure of a lymph node.

A. Neutrophils are a type of white blood cell that primarily responds to bacterial infections and perform phagocytosis, not specifically attacking tumor or virus-infected cells.
B. Regulatory T cells help regulate the immune response and prevent excessive immune activity, but they do not directly attack tumor or virus-infected cells.
C. Natural killer (NK) cells are a type of lymphocyte that plays a key role in the body's defense against tumor cells and virus-infected cells by directly attacking and destroying them.
D. Memory T cells are responsible for "remembering" a previous pathogen, enabling a quicker response upon future exposure, but they do not directly attack tumor or virus-infected cells.