T - cells mature in?: (A) Bone marrow, (B) Liver, (C) Thymus, (D) Lymph nodes
Answer is C. Ans is 'c' i.e., Thymus o T cell precursors arise in bone marrow (also in yolk sac & liver before birth) 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).o B cells originate as well as mature in bone marrow.