Which character is found only in mammales ?

Options

A. Neck
B. Diaphragm
C. Optic lobes of brain
D. Tail

Answer

To determine which character is found only in mammals, we can analyze the options provided: neck, diaphragm, optic lobes of the brain, and tail.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are neck, diaphragm, optic lobes of the brain, and tail.

2. **Analyze Each Option**:
- **Neck**: This structure is present in many animal groups, including birds, reptiles, and mammals. Therefore, it is not exclusive to mammals.
- **Diaphragm**: The diaphragm is a muscular structure that separates the thoracic cavity from the abdominal cavity and is crucial for respiration. It is a characteristic feature of mammals and is not found in other animal groups.
- **Optic Lobes of the Brain**: These are present in various vertebrates, including birds and reptiles, so they are not exclusive to mammals.
- **Tail**: Many animals, including reptiles and some amphibians, have tails. Thus, this feature is also not exclusive to mammals.

3. **Conclusion**: After analyzing all the options, the diaphragm is the only structure that is found exclusively in mammals.

### Final Answer: Diaphragm

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