Final answer:
Secondary lymphoid tissues house mature lymphocytes, while primary lymphoid tissues are where lymphocytes originate and mature, like bone marrow for B cells and thymus for T cells. The spleen, a secondary lymphoid tissue, filters blood and captures pathogens.
Step-by-step explanation:
The correct answer to the question about primary and secondary lymphoid tissues is d) Secondary lymphoid tissues house mature lymphocytes. Primary lymphoid tissues, including the bone marrow and thymus, are where lymphocytes originate and mature. B cells mature within the bone marrow, while T cells mature in the thymus. Secondary lymphoid tissues, such as lymph nodes and the spleen, function as areas where these mature lymphocytes reside and respond to antigens. These secondary sites are integral to the adaptive immune response. They do not produce antibodies; that function is reserved for plasma cells, which differentiate from B cells. They also filter lymph, but do not filter blood, though the spleen, as a secondary lymphoid organ, does have a role in blood filtration.