The mode of excretion in which animal excrete urea as major excretory waste is called

Options

A. (a) Ureotelism
B. (b) Uricotelism
C. (c) Ammonotelism
D. (d) Aminotelism

Answer

To solve the question regarding the mode of excretion in animals that primarily excrete urea, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Excretion**:
- Excretion is the process by which animals eliminate waste products from their bodies. The nature of these waste products can vary based on the organism and its environment.

2. **Types of Nitrogenous Wastes**:
- The primary nitrogenous wastes produced by animals include:
- **Urea**: Excreted by ureotelic organisms.
- **Uric Acid**: Excreted by uricotelic organisms.
- **Ammonia**: Excreted by ammonotelic organisms.
- **Amino Acids**: Excreted by aminotelic organisms.

3. **Identifying Ureotelism**:
- Organisms that primarily excrete urea are referred to as ureotelic organisms. The mode of excretion for these organisms is termed **ureotelism**.

4. **Eliminating Other Options**:
- Uricotelism refers to the excretion of uric acid.
- Ammonotelism refers to the excretion of ammonia.
- Aminotelism refers to the excretion of amino acids.
- Since the question specifically asks about urea, the other options can be eliminated.

5. **Conclusion**:
- Therefore, the correct answer to the question is **ureotelism**, as it specifically refers to the mode of excretion where urea is the major waste product.

### Final Answer:
**Ureotelism**