Amphibians are

Options

A. amninotes
B. anomniotes
C. homoeothermic
D. none tetrapod vertebrates.

Answer

### Step-by-Step Solution:

1. **Understanding Amphibians**: Amphibians are a class of animals that can live both in water and on land. This dual lifestyle is a defining characteristic of this group.

2. **Identifying the Options**: The question provides four options:
- Amniotes
- Anamniotes
- Homeothermic
- Non-tetrapod vertebrates

3. **Defining Amniotes and Anamniotes**:
- **Amniotes**: These are vertebrates that lay eggs on land or retain the fertilized egg within the mother. Examples include reptiles, birds, and mammals.
- **Anamniotes**: These are vertebrates that lay eggs in water and do not have an amnion (a protective membrane). Amphibians fall into this category.

4. **Examining Homeothermic and Non-tetrapod Vertebrates**:
- **Homeothermic**: This term refers to animals that maintain a constant body temperature regardless of the environment. Most amphibians are not homeothermic; they are ectothermic (cold-blooded).
- **Non-tetrapod Vertebrates**: This category includes fish and other vertebrates that do not have four limbs. Amphibians, being tetrapods, do not fit into this category.

5. **Conclusion**: Based on the definitions and characteristics discussed, amphibians are classified as **anamniotes** because they lay their eggs in water.

### Final Answer:
Amphibians are **anamniotes**.

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