Hormone which play a major role is differentiation in T-Lymphocyte is

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the hormone that plays a major role in the differentiation of T-lymphocytes. Differentiation refers to the process by which T-lymphocytes develop into specialized immune cells.

2. **Defining T-Lymphocyte Differentiation**: T-lymphocytes, or T-cells, are a type of white blood cell that plays a crucial role in the immune response. Differentiation means that these cells will develop into specific types of T-cells that perform distinct functions, such as cytotoxic T-cells that kill infected cells.

3. **Identifying the Hormone**: The hormone responsible for the differentiation of T-lymphocytes is thymosin. Thymosin is produced by the thymus gland, which is essential for the maturation and differentiation of T-cells.

4. **Role of Thymosin**: Thymosin stimulates the development of T-cells and promotes their specialization into various types of immune cells. This hormone is crucial for ensuring that T-lymphocytes can effectively respond to pathogens.

5. **Conclusion**: Therefore, the hormone that plays a major role in the differentiation of T-lymphocytes is **thymosin**.

### Final Answer:
The hormone which plays a major role in the differentiation of T-lymphocytes is **thymosin**.

---