Final answer:
Secondary lymphatic organs include the spleen, lymph nodes, and tonsils, which are involved in filtering lymph, storing lymphocytes, and activating immune responses. Bone marrow, however, is a primary lymphatic organ and is not included in this category.
Step-by-step explanation:
The secondary lymphatic organs, which include the spleen, lymph nodes, and tonsils, are integral in cleansing blood and lymph, and in initiating most adaptive immune responses. These organs filter lymph, store lymphocytes, and are sites where pathogens can encounter and activate these lymphocytes, triggering an immune response. The spleen particularly filters blood, removing pathogens and damaged blood cells, while lymph nodes are key sites for lymphocyte concentration and sensitization upon first exposure to an antigen. On the other hand, the bone marrow is a primary lymphatic organ where B cells mature and is not considered a secondary lymphatic organ.