Which of the following would NOT be classified as a lymphoid organ?

A) Peyer's patches of the intestine

B) pancreas

C) spleen

D) tonsils

Answer: B. Pancreas

Explanation:

Lymphoid organs can be grouped into Primary and Secondary.

Primary Lymphoid Organs include; Thymus and Bone Marrow, responsible for the provision of micro-environments to aid the development and maturation of T-lymphocytes.

Secondary Lymphoid Organs include; Spleen, Peyer's patches of the intestine, Tonsils, Adenoids, Lymph nodes and Appendix. Together, they provide the environment for the interaction of lymphocytes with the antigen, which then multipy to become effector cells.