Which are vestigial in humans?

Options

A. Tail vertebrate
B. Auricular muscles
C. Scalp muscles
D. All the above

Answer

### Step-by-Step Solution:

1. **Understanding Vestigial Structures**:
- Vestigial structures are remnants of organs or parts that had a function in an early ancestor but are no longer functional in the same way in the current organism. In humans, these structures provide insight into our evolutionary history.

2. **Identifying the Options**:
- The question provides four options to identify which structures are vestigial in humans:
1. Tail vertebrae
2. Auricular muscles
3. Scalp muscles
4. All of the above

3. **Analyzing Each Option**:
- **Tail Vertebrae**:
- Humans are born with a small tail (the coccyx), which is a remnant of a tail that our ancestors had. This structure is considered vestigial as it no longer serves the purpose of a functional tail.
- **Auricular Muscles**:
- These are muscles around the human ear that allow for slight movement of the ear. In many animals, these muscles are used for directional hearing, but in humans, they are largely non-functional, making them vestigial.
- **Scalp Muscles**:
- The muscles in the scalp (such as the occipitofrontalis) allow for movement of the scalp and are remnants of muscles that were more functional in our ancestors for various purposes, including communication through facial expressions.

4. **Conclusion**:
- Since all three options (tail vertebrae, auricular muscles, and scalp muscles) are vestigial structures in humans, the correct answer is **"All of the above."**

### Final Answer:
All of the above (tail vertebrae, auricular muscles, scalp muscles) are vestigial in humans.

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