Chelones resemble birds in having

Options

A. Four chambered heart
B. Beaked toothless jaws
C. Inelastic lungs
D. Presence of diaphragm.

Answer

### Step-by-Step Solution:

1. **Understanding Chelones**:
- Chelones refer to turtles and tortoises, which belong to the class Reptilia. They are characterized by their hard shells that cover their ribcage.

2. **Analyzing the Options**:
- We have several options to consider:
1. Four-chambered heart
2. Beak, toothless jaws
3. Inelastic lungs
4. Presence of diaphragm

3. **Evaluating Each Option**:
- **Option 1: Four-chambered heart**:
- Reptiles, including Chelones, typically have a three-chambered heart. Therefore, this option is incorrect.

- **Option 2: Beak, toothless jaws**:
- Both Chelones and birds possess beaked, toothless jaws. This is a significant common feature, making this option correct.

- **Option 3: Inelastic lungs**:
- Chelones have inelastic lungs, while birds have elastic lungs. Thus, this option is incorrect.

- **Option 4: Presence of diaphragm**:
- Birds do not have a diaphragm, which means this option is also incorrect.

4. **Conclusion**:
- After evaluating all the options, the only feature that Chelones and birds have in common is the beaked, toothless jaws. Therefore, the correct answer is that Chelones resemble birds in having beaked, toothless jaws.

### Final Answer:
Chelones resemble birds in having beaked, toothless jaws.

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