In comparison to urea ammonia is

Options

A. Less toxic
B. Toxic
C. Highly toxic
D. None

Answer

**Step-by-Step Solution:**

1. **Understanding Nitrogenous Wastes:**
- Organisms excrete nitrogenous wastes in different forms: ammonia, urea, and uric acid.
- These wastes vary in toxicity and the amount of water required for excretion.

2. **Identifying Ammonia:**
- Ammonia is the most toxic form of nitrogenous waste.
- It is primarily excreted by aquatic organisms (ammonotelic organisms) because they have access to large amounts of water, which helps dilute the toxicity.

3. **Identifying Urea:**
- Urea is less toxic than ammonia and is excreted by ureotelic organisms, such as mammals and amphibians.
- The process of excreting urea requires more energy compared to ammonia.

4. **Comparing Toxicity:**
- Since ammonia is the most toxic nitrogenous waste, in comparison to urea, ammonia is indeed highly toxic.
- Therefore, the correct answer to the question is that ammonia is "highly toxic" in comparison to urea.

5. **Conclusion:**
- The correct option is that ammonia is "highly toxic" compared to urea.