Final answer:
Cells active in both innate and adaptive immunity develop from common pluripotent precursors in the bone marrow called stem cells. a) B cells mature in the bone marrow, while T cells migrate to the thymus for maturation.
Step-by-step explanation:
Cells active in both innate and adaptive immunity develop from common pluripotent precursors in the bone marrow called stem cells. These cells originate from hematopoietic stem cells in the bone marrow and differentiate into various immune cells. B cells, which are part of the adaptive immune system, mature in the bone marrow. T cells migrate from the bone marrow to the thymus for maturation.