Regarding the Lymphoid Organs and the immune system, which statements are true?
a. Primary lymphoid organs (bone marrow and thymus) are where lymphocytes originate and mature.
b. The spleen acts as a filter of the blood, trapping blood-borne microorganisms and serving as a large reservoir of erythrocytes.
c. The thymus is quite large at birth but keeps reducing in size after puberty is attained.
d. MALT (Mucosa-Associated Lymphoid Tissue) constitutes about 50 per cent of the lymphoid tissue in the human body.
e. Lymph nodes serve to trap antigens that enter the lymph and tissue fluid, activating the lymphocytes there.
