Which of the following traits is not characteristic of amphibians?

Options

A. Skin is moist and without scales
B. Cloaca is present
C. Dioecious, external fertilization, oviparous, indirect development
D. Amniotic egg is present

Answer

To determine which trait is not characteristic of amphibians, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Option A: Skin moist or without scales**
- Amphibians are known for having moist skin that lacks scales. This trait is characteristic of amphibians as it helps them in respiration and moisture absorption. Therefore, this option is characteristic of amphibians.

2. **Option B: Cloaca is present**
- Amphibians possess a cloaca, which is a common opening for excretion and reproduction. This trait is indeed characteristic of amphibians. Thus, this option is also characteristic of amphibians.

3. **Option C: External fertilization, oviparous, and indirect development**
- Most amphibians reproduce through external fertilization, laying eggs in water (oviparous), and undergo indirect development (larval stage). This is a well-known characteristic of amphibians. Therefore, this option is characteristic of amphibians as well.

4. **Option D: Amniotic egg is present**
- Amphibians do not have amniotic eggs. Amniotic eggs are a characteristic of reptiles, birds, and some mammals, providing protection and a suitable environment for the developing embryo. Amphibians lay non-amniotic eggs, which are typically laid in water and do not have the protective shell found in amniotic eggs. Thus, this option is NOT characteristic of amphibians.

### Conclusion:
The trait that is not characteristic of amphibians is **Option D: Amniotic egg is present**.

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