The site where lymphocytes interact with antigens and proliferate to become effector cells are

Options

A. spleen and lymph nodes
B. bone marrow and thymus
C. Peyers patches and tonsils
D. Both (a) and (c )

Explanation

**Step-by-Step Solution:**

1. **Understanding Lymphocytes**: Lymphocytes are a type of white blood cell that play a crucial role in the immune response. They are initially immature and need to mature to become effective in fighting infections.

2. **Primary Lymphoid Organs**: The maturation of lymphocytes occurs in primary lymphoid organs, which include the bone marrow and thymus. In these organs, lymphocytes differentiate into antigen-sensitive cells.

3. **Secondary Lymphoid Organs**: After maturation, these antigen-sensitive lymphocytes migrate to secondary lymphoid organs. The primary function of these organs is to provide a site for lymphocytes to interact with antigens.

4. **Examples of Secondary Lymphoid Organs**: The secondary lymphoid organs include the spleen, lymph nodes, tonsils, and Peyer’s patches. These organs are essential for the immune response as they facilitate the interaction between lymphocytes and antigens.

5. **Interaction and Proliferation**: In the secondary lymphoid organs, lymphocytes interact with antigens and proliferate to become effector cells, which are crucial for mounting an immune response.

6. **Conclusion**: Based on the above points, the sites where lymphocytes interact with antigens and proliferate to become effector cells are the secondary lymphoid organs, specifically the spleen and lymph nodes, as well as tonsils and Peyer’s patches.

7. **Final Answer**: Therefore, the correct answer to the question is option D: both A (spleen and lymph nodes) and C (tonsils).

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