Helper cells belong to -
Ans. is 'a' i..e.,T cells T-cells . T cells are amongst the two impoant cells of adaptive immune system (others are B-cells). . T cell precursors arise in bone marrow (also in yolk sac & liver before bih) and migrate to the thymus. . Maturity of T-cells takes place in the thymus (So, T cells arise in bone marrow and mature in thymus).
T cells
Macrophages
B cells
Monocytes