Helper cells belong to -: (A) T cells, (B) Macrophages, (C) B cells, (D) Monocytes
Answer is A. 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).