Which one of the following characters is not typical of the class Mammalia

Options

A. Thecodont dentition
B. Alveolar lungs
C. Ten pairs of cranial nerves
D. Seven cervical vertebrae

Answer

To determine which character is not typical of the class Mammalia, we need to analyze the characteristics of mammals. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Characteristics of Mammals
Mammals are characterized by several key features:
- They breathe through lungs, which are alveolar in nature.
- They possess seven cervical vertebrae, regardless of the size of the mammal.
- They have thecodont dentition, which means their teeth are set in sockets.
- They have twelve pairs of cranial nerves.

### Step 2: Analyze the Options
Now, let’s look at the options provided:
- **A. Thecodont dentition**: This is a typical characteristic of mammals.
- **B. Alveolar lungs**: This is also a typical characteristic of mammals.
- **C. 10 pairs of cranial nerves**: This is not typical of mammals, as they have 12 pairs of cranial nerves.
- **D. 7 cervical vertebrae**: This is a typical characteristic of mammals.

### Step 3: Conclusion
Based on the analysis, the option that is not typical of the class Mammalia is:
**C. 10 pairs of cranial nerves**.

### Final Answer
The correct answer is **C. 10 pairs of cranial nerves**.

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