Humans are

Options

A. Ammonotelic
B. Ureotelic
C. Uricotelic
D. Both B and C

Answer

### Step-by-Step Solution

1. **Understanding the Terms**:
- **Ammonotelic**: Organisms that excrete ammonia as their primary nitrogenous waste. Typically found in aquatic animals.
- **Ureotelic**: Organisms that excrete urea as their primary nitrogenous waste. This is characteristic of mammals, including humans.
- **Uricotelic**: Organisms that excrete uric acid as their primary nitrogenous waste. Common in birds and reptiles.

2. **Identifying Human Excretion**:
- Humans primarily excrete urea, which is less toxic than ammonia. This is a key characteristic of ureotelic organisms.

3. **Process of Urea Formation**:
- In humans, excess proteins are broken down through a process called **deamination**, where the amino group (NH2) is removed from amino acids.
- This process occurs mainly in the liver, converting the amino group into ammonium ions.

4. **Urea Cycle**:
- The ammonium ions are then converted into urea through a series of reactions known as the **urea cycle** in the liver. Urea is less toxic and can be safely transported in the bloodstream.

5. **Excretion of Urea**:
- Once formed, urea is transported via the bloodstream to the kidneys, where it is filtered out and excreted from the body through urine.

6. **Conclusion**:
- Based on the above information, humans are classified as **ureotelic** organisms because they primarily excrete urea.

### Final Answer:
Humans are ureotelic organisms.