Final answer:
The spleen's red pulp is involved in blood filtration, removing damaged red blood cells, while the white pulp is focused on immunity, housing lymphocytes that remove pathogens and facilitate adaptive immune responses. (option 3 is the correct answer)
Step-by-step explanation:
The spleen is a secondary lymphoid organ that plays a crucial role in both blood filtration and immune response. The red pulp of the spleen is primarily concerned with the filtration of the blood, where it removes degenerating or damaged red blood cells and recycles them. In contrast, the white pulp is mainly associated with immunity, where it is enriched with lymphocytes that are responsible for removing antigen-coated bacteria from the blood and facilitating the adaptive immune response.
Specifically, the red pulp contains reticular fibers, fixed and free macrophages, and other typical blood cells while performing the filtering function. The white pulp surrounds the central arterioles and consists of germinal centers filled with B cells, surrounded by T cells and accessory immune cells such as macrophages and dendritic cells, playing a key role in the adaptive immune system by mounting T and B cell responses.