Which of the following are considered viral vaccines? (Select all that apply)

A. Lymph nodes are secondary lymphoid organs where B and T cells can be activated, but they are not the cells themselves.
B. Tonsils are lymphoid tissues that help protect against pathogens, but they are not the cells themselves.
C. Lymphocytes are the correct answer. B cells and T cells are types of lymphocytes, which are white blood cells involved in the adaptive immune response.
D. Antibodies are proteins produced by B cells (specifically plasma cells) in response to pathogens, but they are not cells themselves.

A. The portal of entry is the specific site or pathway through which a pathogen enters the body, such as the skin, mucous membranes, or respiratory and digestive tracts.
B. Blood is not the site of entry but rather a medium that can carry pathogens throughout the body once they have entered through a portal of entry.
C. The respiratory tract is a common portal of entry for many pathogens (like viruses or bacteria), but it is just one example of a portal of entry, not the general term for it.
D. Inflammation is an immune response to infection or injury, not a site of entry for