Name the main excretory organ of vertebrates.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Excretory Organs**: Excretory organs are responsible for the elimination of waste products from the body. These wastes can include metabolic waste, nutrients, gaseous substances, and nitrogenous waste.

2. **Identifying Excretory Organs in Vertebrates**: In vertebrates, there are several organs that perform excretory functions. The primary excretory organs include:
- **Kidneys**: The main excretory organs responsible for filtering blood and eliminating nitrogenous waste.
- **Skin**: Eliminates waste through sweat, which can include unwanted nutrients and ions.
- **Lungs**: Excrete carbon dioxide, a gaseous waste product of metabolism.
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