A reptilean character of protherian is presence of

Options

A. Left aortic arch
B. T-shaped clavicle
C. Diaphragm
D. Seven cervical vertebrae.

Answer

To answer the question "A reptilian character of prototherian is presence of," we will analyze the given options step by step.

### Step-by-Step Solution:

1. **Understanding Prototherians**:
- Prototherians are a subclass of mammals known for laying eggs instead of giving live birth, which is a characteristic that links them to reptiles.

2. **Evaluating the Options**:
- **Option A: Left Aortic Arch**:
- The left aortic arch is a feature found in mammals. It arises from the left ventricle and is not a characteristic of reptiles. Therefore, this option is incorrect.

- **Option B: T-shaped Clavicle**:
- Mammals typically have an S-shaped clavicle (collarbone). A T-shaped clavicle is not characteristic of mammals or reptiles. Thus, this option is also incorrect.

- **Option C: Diaphragm**:
- The diaphragm is a muscle that aids in respiration and is present in both mammals and reptiles. This is a shared characteristic, making this option a potential answer.

- **Option D: 7 Cervical Vertebrae**:
- The presence of 7 cervical vertebrae is a characteristic feature of mammals. Reptiles do not have this specific count of cervical vertebrae. Therefore, this option is incorrect.

3. **Conclusion**:
- The correct answer is **diaphragm**, as it is a reptilian character that is also present in prototherians.

### Final Answer:
The reptilian character of prototherian is the presence of **diaphragm**.

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