The secondary lymphoid organs:

• A. Are where foreign antigens interact with lymphocytes.
• B. Are the site of antibody production.
• C. Are hematopoietic.
• D. Include bone marrow & thymus.

Answer: (A)

Verified step by step guidance

1. Understand the role of secondary lymphoid organs in the immune system. These organs are crucial for the interaction between foreign antigens and lymphocytes, which are a type of white blood cell involved in the immune response.
2. Recognize that secondary lymphoid organs are sites where antibody production occurs. Antibodies are proteins that help neutralize pathogens, and their production is a key function of these organs.
3. Differentiate between primary and secondary lymphoid organs. Primary lymphoid organs, such as the bone marrow and thymus, are involved in the production and maturation of lymphocytes, whereas secondary lymphoid organs are involved in the activation of these cells.
4. Identify examples of secondary lymphoid organs, which include the lymph nodes, spleen, and mucosal-associated lymphoid tissues (MALT). These organs provide an environment for immune cells to interact with antigens.
5. Clarify that secondary lymphoid organs are not hematopoietic. Hematopoiesis, the process of blood cell formation, primarily occurs in the bone marrow, which is a primary lymphoid organ.