Lymph nodes are secondary lymphoid organs. Explain the role of lymph nodes in our immune response.

Explanation

**Step-by-Step Solution:**

1. **Introduction to Lymph Nodes**: Lymph nodes are small, bean-shaped structures that are part of the lymphatic system, which is crucial for the immune response. They are classified as secondary lymphoid organs, alongside the spleen and tonsils.

2. **Function of Lymph Nodes**: The primary role of lymph nodes in the immune response is to filter lymph fluid. They act as checkpoints where lymph fluid, which contains pathogens and foreign substances, is examined by the immune system.

3. **Trapping Microorganisms and Antigens**: Lymph nodes trap microorganisms (such as bacteria and viruses) and antigens (foreign substances that provoke an immune response). When lymph fluid enters the lymph nodes, these harmful agents are captured and held within the node.

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