Which one is not vestigial in humans?

Options

A. Tail bone
B. Ear muscle
C. Wisdom teeth
D. Finger nails.

Answer

**Step-by-Step Solution:**

1. **Understanding Vestigial Organs**:
- Vestigial organs are non-functional remnants of organs that were once functional in our ancestors. They are reduced in size and serve little to no purpose in the current organism.

2. **Analyzing the Options**:
- We have four options to consider: tailbone, ear muscles, wisdom teeth, and fingernails.

3. **Evaluating Each Option**:
- **Tailbone**: This is a vestigial organ. It is a remnant of a tail that was used for balance in our ancestors but serves no significant purpose in modern humans.
- **Ear Muscles**: These are also considered vestigial. They were useful for moving the ears in our ancestors for better hearing, but they are not functional in humans today.
- **Wisdom Teeth**: These teeth were useful for our ancestors who had a different diet and less dental hygiene. They are considered vestigial as they are not necessary for modern humans.
- **Fingernails**: Unlike the other options, fingernails are not vestigial. They serve a purpose in offense, defense, and protection of the fingertips. They are not reduced in size and continue to grow, which distinguishes them from vestigial organs.

4. **Conclusion**:
- The correct answer to the question "Which one is not vestigial in humans?" is **fingernails**.

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