Major roles of thymus gland in humans is/are

Options

A. Differentiation of T-lymphocytes
B. Differentiation of B-lymphocytes
C. Promote production of antibodies
D. Both (1) and (3)

Answer

### Step-by-Step Solution:

1. **Identify the Location of the Thymus Gland**:
- The thymus gland is located in the chest, specifically behind the breastbone (sternum).

2. **Understand the Function of the Thymus Gland**:
- The thymus gland plays a crucial role in the immune system. Its primary function is to produce immune cells.

3. **Focus on the Type of Immune Cells Produced**:
- The thymus gland is primarily responsible for the production and maturation of T lymphocytes (T cells), which are a type of white blood cell.

4. **Explain the Role of T Lymphocytes**:
- T lymphocytes are essential for the immune response as they help in fighting infections and maintaining the body’s defense against pathogens.

5. **Differentiate Between T and B Lymphocytes**:
- It is important to note that the thymus gland is involved in the maturation of T lymphocytes only, not B lymphocytes. B lymphocytes are produced and mature in the bone marrow.

6. **Conclude the Major Role of the Thymus Gland**:
- Therefore, the major role of the thymus gland in humans is the differentiation and maturation of T lymphocytes.

### Final Answer:
The major role of the thymus gland in humans is the differentiation and maturation of T lymphocytes.

---