Give the functions of lymph nodes.

Explanation

### Step-by-Step Solution:

1. **Definition of Lymph Nodes**: Lymph nodes are small, bean-shaped structures located throughout the lymphatic system. They play a crucial role in the immune system.

2. **Function of Lymph Nodes**:
- **Filtration of Lymph**: Lymph nodes filter lymph fluid, which is a clear fluid that circulates through the lymphatic system. This filtration process helps to remove harmful substances.

- **Production of Lymphocytes**: Lymph nodes are sites where lymphocytes (a type of white blood cell) are produced. These cells are essential for the immune response, helping the body to fight off infections.
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