Aves are

Options

A. Ammonotelic
B. Uricotelic
C. Ureotelic
D. Both (1) & (3)

Answer

### Step-by-Step Solution

1. **Understanding Aves**: Aves is the scientific term used to refer to birds. All birds belong to this class in the animal kingdom.

2. **Identifying Excretory Types**: The question asks about the type of nitrogenous waste excretion in Aves. The options provided are:
- Monotelic
- Uricotelic
- Ureotelic
- Both 1 and 3

3. **Defining Monotelic**: Monotelic organisms excrete nitrogenous wastes primarily in the form of ammonia. This method is common in aquatic animals, as ammonia is highly soluble in water but also highly toxic. Therefore, it requires a large amount of water for excretion.

4. **Defining Uricotelic**: Uricotelic organisms excrete nitrogenous wastes in the form of uric acid. This waste is less toxic and is excreted as a semi-solid paste, requiring much less water for elimination. Birds, along with some reptiles and insects, fall into this category.

5. **Defining Ureotelic**: Ureotelic organisms excrete nitrogenous wastes in the form of urea. This method is less toxic than ammonia and is common in mammals and adult amphibians.

6. **Analyzing Aves**: Since Aves (birds) excrete nitrogenous waste primarily in the form of uric acid, they are classified as uricotelic organisms.

7. **Conclusion**: Based on the definitions and the characteristics of Aves, the correct answer to the question is that Aves are **uricotelic**.

### Final Answer
Aves are **uricotelic**.

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