What is the main function of the bone marrow in the human body?

Step-by-step solution

The primary lymphoid organs in the human body are the bone marrow and thymus, where immature lymphocytes differentiate into antigen-sensitive lymphocytes.The bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced. It provides micro-environments for the development and maturation of T-lymphocytes. The thymus is quite large at the time of birth but keeps reducing in size with age. By the time puberty is attained, it reduces to a very small size.