Read the following statements regarding the human immune system: (A) Primary lymphoid organs provide the sites for interaction of lymphocytes with the antigen. (B) Both B-lymphocytes and T-lymphocytes originate in the bone marrow. (C) Spleen has a large reservoir of erythrocytes. (D) Mucosa-Associated Lymphoid Tissue (MALT) constitutes about 20 percent of the lymphoid tissue in human body. How many of the above state

Step-by-step solution

Statement (A) is incorrect because secondary lymphoid organs (like spleen, lymph nodes, tonsils) provide the sites for interaction of lymphocytes with the antigen, not primary lymphoid organs. Statement (B) is correct as the bone marrow is the main lymphoid organ where all blood cells, including both B and T lymphocytes, are produced. Statement (C) is correct as the spleen acts as a filter of the blood and has a large reservoir of erythrocytes. Statement (D) is incorrect because Mucosa-Associated Lymphoid Tissue (M