A vestigial organ in human is

Options

A. Ear pinna
B. Nictitating membrane
C. Mammary glands in males
D. Knee bone.

Answer

**Step-by-Step Solution:**

1. **Understanding Vestigial Organs**:
- A vestigial organ is defined as a structure that has lost most or all of its original function through the course of evolution.

2. **Identifying Examples of Vestigial Organs in Humans**:
- In humans, several structures are considered vestigial. Examples include:
- Auricular muscles (muscles around the ear)
- Wisdom teeth
- Vermiform appendix
- Body hair
- Nictitating membrane (a small fold in the corner of the eye)

3. **Analyzing the Given Options**:
- The options provided are:
- Ear
- Pinna
- Nictitating membrane
- Mammary glands in males
- Knee bone
- Among these, we need to identify which one is recognized as a vestigial organ.

4. **Determining the Correct Answer**:
- The nictitating membrane is a remnant of a third eyelid found in some animals, which has lost its primary function in humans. Therefore, it is classified as a vestigial organ.

5. **Final Answer**:
- The vestigial organ in humans is the **nictitating membrane**.

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