Question

Which of the following are secondary lymphoid organs?

Options

• Heart and lungs

• Bone marrow and thymus

• Brain and spinal cord

• Spleen, lymph nodes, tonsils, and MALT

Answer 1

Secondary lymphoid organs include the spleen, lymph nodes, tonsils, and MALT (mucosa-associated lymphoid tissue). These provide specific sites where mature lymphocytes interact with antigens and proliferate to mount immune responses.