Define ammonotelism. Name the excretory organs of flatworms.

Explanation

### Step-by-Step Solution:

1. **Define Ammonotelism**:
- Ammonotelism is a biological process by which organisms excrete nitrogenous wastes primarily in the form of ammonia. This method of excretion is common in aquatic animals, such as bony fish, because ammonia is highly soluble in water and can be easily diluted and eliminated from the body.

2. **Identify the Excretory Organs of Flatworms**:
- Flatworms belong to the phylum Platyhelminthes. The primary excretory organs in flatworms are called **Protonephridia**. These structures are composed of flame cells, which are specialized cells that help in the excretion of waste products. Protonephridia are typically located along the lateral sides of the flatworm's body and function to remove excess water and nitrogenous wastes.

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