Which structure of the male reproductive system from the following image stores the mature sperm before ejaculation?

A. Producing early induced proteins: While natural killer cells can produce cytokines, their primary function is not related to protein production.

B. Promoting opsonization of bacteria cells: Opsonization is primarily performed by antibodies and complement proteins, rather than natural killer cells.

C. Secreting signaling molecules: While natural killer cells do secrete signaling molecules (cytokines) to communicate with other immune cells, their main role is the direct destruction of infected cells.

D. Destroying virally infected cells: The primary function of natural killer cells is to recognize and eliminate virally infected cells and tumor cells, contributing to the innate immune response.

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