The primary lymphoid organs are – Bone marrow and Thymus.
In primary lymphoid organs immature lymphocytes differentiate and result into the production of antigen sensitive lymphocytes
Thus the primary lymphoid organs produce lymphocytes.
Secondary lymphoid organs include – Lymph nodes, spleen, tonsils, peyer’s patches of small intestine and appendix.
Final Answer
Thus the correct answer is the primary lymphoid organs are – Bone marrow and Thymus.
Secondary lymphoid organs include – Lymph nodes, spleen, tonsils, peyer’s patches of small intestine and appendix.