Ureotelism occurs in

Options

A. Mammals
B. Aquatic insects
C. Tadpoles
D. Birds

Answer

**Step-by-Step Solution:**

1. **Understanding Ureotelism**: Ureotelism refers to the excretion of nitrogenous waste primarily in the form of urea. This process is typical of certain organisms that need to conserve water while eliminating waste.

2. **Identifying Ureotelic Organisms**: Ureotelism is commonly found in terrestrial animals, particularly mammals. These animals produce urea as their main nitrogenous waste product because they have limited access to water and need to minimize water loss.

3. **Analyzing the Options**:
- **Option A: Mammals**: Mammals are known to excrete urea, making them ureotelic. This option is likely correct.
- **Option B: Aquatic Insects**: These organisms typically excrete ammonia, not urea, so they are not ureotelic. This option is incorrect.
- **Option C: Tadpoles**: Tadpoles primarily excrete ammonia, making them ammonotelic. This option is also incorrect.
- **Option D: Birds**: Birds excrete uric acid, which classifies them as uricotelic, not ureotelic. This option is incorrect.

4. **Conclusion**: Based on the analysis of the options, the correct answer is **Option A: Mammals**, as they are the organisms that exhibit ureotelism.