Four chambered heart occurs in

Options

A. Amphibia
B. Chelonia
C. Birds and Crocodilia
D. Ophidia

Answer

To solve the question "Four chambered heart occurs in," we will analyze each option provided and determine which of the animals listed possess a four-chambered heart.

### Step-by-Step Solution:

1. **Understanding the Heart Structure**:
- A four-chambered heart consists of two atria and two ventricles, allowing for efficient separation of oxygenated and deoxygenated blood.

2. **Analyzing the Options**:
- **Option 1: Amphibia**:
- Amphibians, such as frogs and toads, have a three-chambered heart (two atria and one ventricle). Therefore, this option is incorrect.

- **Option 2: Chelonia**:
- Chelonia refers to turtles and tortoises, which are reptiles. Reptiles typically have a three-chambered heart. Hence, this option is also incorrect.

- **Option 3: Birds and Crocodilia**:
- Birds possess a four-chambered heart, which is highly efficient for their high metabolic needs. Crocodiles, while being reptiles, are an exception as they also have a four-chambered heart. Thus, this option is correct.

- **Option 4: Ophidia**:
- Ophidia refers to snakes, which are reptiles and have a three-chambered heart. Therefore, this option is incorrect.

3. **Conclusion**:
- The correct answer is **Option 3: Birds and Crocodilia**, as both birds and crocodiles possess a four-chambered heart.

### Final Answer:
The four-chambered heart occurs in **birds and crocodilia**.

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