Which characters is not same in aves and mammals

Options

A. Single systemic arch
B. Metanephric kidney
C. Seven cerviaal vertebrae
D. Homeotherms

Answer

To determine which character is not the same in aves (birds) and mammals, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Common Characteristics**:
- Both aves and mammals have a **single systemic arch**. This means they have a single pathway for blood circulation from the heart to the body.
- They both possess **metanephric kidneys**, which are the permanent kidneys present in embryos.
- Both groups are classified as **warm-blooded animals** (homotherms), meaning they can regulate their body temperature regardless of the environment.

2. **Identify Differences**:
- One notable difference between aves and mammals is the **number of cervical vertebrae**.
- In mammals, there are typically **seven cervical vertebrae**.
- In aves, the number of cervical vertebrae can range from **13 to 25**.

3. **Conclusion**:
- The character that is not the same in aves and mammals is the **number of cervical vertebrae**.

### Final Answer:
The character that is not the same in aves and mammals is the **number of cervical vertebrae**.

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