Name the excretory organs of flatworm, round worm, annelids and insects.

Explanation

To answer the question regarding the excretory organs of flatworms, roundworms, annelids, and insects, we can break down the information as follows:

### Step-by-Step Solution:

1. **Flatworms (Phylum Platyhelminthes)**:
- The excretory organs in flatworms are called **flame cells**.
- These flame cells are specialized cells that help in the removal of waste products.
- When grouped together, flame cells form a structure known as **protonephridia**, which is responsible for excretion in flatworms.
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