What is the name of the outer layer of the lungs that connects to the thoracic wall?

A. Eosinophil: Eosinophils are involved in allergic reactions and parasitic infections, but they are not responsible for B and T cell functions.

B. Basophil: Basophils are involved in inflammatory responses, particularly releasing histamine, but do not include B or T cells.

C. Monocyte: Monocytes are large white blood cells that develop into macrophages but do not include B or T cells.

D. Lymphocyte: Lymphocytes are a subtype of white blood cells that include B cells (which produce antibodies) and T cells (which are involved in cell-mediated immunity), making this the correct answer.

A. NK cells and neutrophils: While NK cells can be found in lymph nodes, neutrophils are not typically housed in lymph nodes; they are more abundant in the bloodstream and tissues during acute inflammation.

B. Lymphocytes and neutrophils: Lymphocytes are indeed housed in lymph nodes, but neutrophils primarily migrate to sites of infection or inflammation rather than residing in lymph nodes.

C. NK cells and complement cells: Natural killer cells can be found in lymph nodes, but complement proteins are not cells; they circulate in the blood and become activated in response to pathogens.

D. Lymphocytes and macrophages: Lymph nodes primarily house lymphocytes (B cells and T cells) and macrophages, which play vital roles in the immune response by filtering lymph and