Amphibian heart is

Options

A. One-chambered
B. Three-chambered
C. Two-chambered
D. Four-chambered

Answer

### Step-by-Step Solution:

1. **Identify the Structure of the Amphibian Heart**:
- Amphibians, such as frogs, have a heart that consists of three chambers.

2. **Understand the Composition of the Heart**:
- The three chambers include one ventricle and two atria.

3. **Blood Flow in the Amphibian Heart**:
- Blood from the ventricle is pumped to two main areas: the lungs and the skin for oxygenation, as well as to the rest of the body.

4. **Mixing of Blood**:
- In the ventricle, oxygenated blood (from the lungs and skin) and deoxygenated blood (returning from the body) mix before being pumped out.

5. **Metabolic Needs of Amphibians**:
- Amphibians have a lower metabolic rate, which means they require less oxygen compared to other animals. This lower demand allows for a less efficient heart structure.

6. **Conclusion**:
- Given the structure and function of the amphibian heart, it is concluded that the amphibian heart is three-chambered, consisting of one ventricle and two atria.

### Final Answer:
The amphibian heart is **three-chambered**.