Lymphocytes that develop immunocompetence in the thymus are

The answer is T cells. They develop from a progenitor lymphoblast ( found in the bone marrow) which could also differentiate into B cells and natural killers cells of the adaptive immune system, through lymphopoiesis. B cells, the other type of lymphocytes, attain immunocompetence in the Gut-associated-lymphoid tissue (GALT).

B umbilical cord it connects the baby and the mother together