why nephridia in earthworm that are basically similar in structure classify into three types ? Mention the names of each .

Explanation

### Step-by-Step Solution:

1. **Understanding Nephridia**: Nephridia are the excretory organs found in earthworms. They are coiled tubular structures that are segmentally arranged throughout the body of the earthworm.

2. **Classification of Nephridia**: Despite their similar structure, nephridia are classified into three distinct types based on their location and function within the earthworm's body.

3. **Types of Nephridia**:
- **Septal Nephridia**: These are located on both sides of the segmental septa, which are the walls separating the segments of the earthworm. They are present from the fifth segment to the last segment and are classified as enteronephric, meaning they are involved in processing the coelomic fluid.
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