Consider the following statements regarding spleen and lymph nodes: 1. The spleen is a large bean-shaped organ mainly containing lymphocytes and phagocytes. 2. The spleen acts as a filter of blood by trapping blood-borne microorganisms. 3. Spleen also has a large reservoir of erythrocytes. 4. Lymph nodes serve to trap microorganisms or other antigens which happen to get into the lymph and tissue fluid. 5. Antigens trapped in lymph nodes are responsible for activation of lymphocytes present there and cause immune response. Choose the correct answer.