Which one of the following statements is incorrect

Options

A. Birds and land snails are uricotelic animals
B. Mammals and frogs are ureotelic animals
C. Aquatic amphibians and aquatic insects are ammonotelic animals
D. Birds and reptiles are ureotelic

Answer

To solve the question "Which one of the following statements is incorrect?", we need to analyze each of the provided options regarding the excretion types of different animals.

### Step-by-Step Solution:

1. **Understand the Types of Nitrogenous Waste Excretion:**
- **Ureotelic:** Animals that excrete urea as their primary nitrogenous waste (e.g., mammals, amphibians).
- **Uricotelic:** Animals that excrete uric acid as their primary nitrogenous waste (e.g., birds, reptiles, land snails).
- **Ammonotelic:** Animals that excrete ammonia, typically aquatic animals (e.g., many fish, aquatic amphibians).

2. **Evaluate Each Option:**
- **Option A:** "Birds and land snails are ureotelic animals."
- This statement is **incorrect** because birds and land snails are actually **uricotelic**; they excrete uric acid.

- **Option B:** "Mammals and frogs are ureotelic animals."
- This statement is **correct** as both mammals and frogs excrete urea.

- **Option C:** "Aquatic amphibians and aquatic insects are ammonotelic animals."
- This statement is **correct**; aquatic amphibians and insects excrete ammonia.

- **Option D:** "Birds and reptiles are ureotelic."
- This statement is **incorrect**; birds and reptiles are **uricotelic** as they excrete uric acid.

3. **Identify the Incorrect Statement:**
- After evaluating all options, we find that **Option A** and **Option D** are incorrect. However, since the question asks for one incorrect statement, we can conclude that the most evident incorrect statement based on common knowledge is **Option D**.

### Conclusion:
- The incorrect statement is **Option D**: "Birds and reptiles are ureotelic."