Nictitating membrane and vermiform appendix of humans are examples of which type of organs.

Explanation

**Step-by-Step Solution:**

1. **Identify the Organs in Question**: The question mentions two specific organs in humans: the nictitating membrane and the vermiform appendix.

2. **Define Vestigial Organs**: Vestigial organs are structures that have lost most or all of their original function through the course of evolution. They are remnants of organs that were fully functional in the ancestors of a species.

3. **Explain the Nictitating Membrane**: The nictitating membrane is a translucent eyelid found in some animals. In humans, it is reduced and serves no significant purpose, making it a vestigial structure. It was functional in some of our ancestors, providing protection and moisture to the eye.

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