B- and T-cells required for immune system are produced in

Options

A. A.Bone marrow cells
B. B.Spleen
C. C.Lymph nodes
D. D.Bone marrw and thymus

Answer

**Step-by-Step Solution:**

1. **Understanding Immune Cells**: The immune system consists of various types of cells, including B-cells and T-cells, which play crucial roles in the body's defense against pathogens.

2. **Origin of Immune Cells**: Both B-cells and T-cells originate from stem cells in the bone marrow. This is the primary site for the production of all blood cells, including immune cells.

3. **Maturation of B-cells**: After their formation in the bone marrow, B-cells remain there to mature. They develop the ability to produce antibodies that are essential for the immune response.

4. **Maturation of T-cells**: In contrast, T-cells, after being produced in the bone marrow, migrate to the thymus gland where they undergo further maturation and differentiation. The thymus is essential for the development of T-cells, but it is not where they are produced.

5. **Conclusion**: Since both B-cells and T-cells are produced in the bone marrow, the correct answer to the question is that B- and T-cells required for the immune system are produced in the bone marrow.

**Final Answer**: Bone marrow.

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