Which one of the following is NOT a vestigeal organ in Human being?

Vestigial organs are those organs which are present in a reduced or non-functional state in an organism but were fully developed and functional in their ancestors.

In human beings, the nictitating membrane (plica semilunaris), vermiform appendix, and coccyx (tailbone) are well-known examples of vestigial organs.

Pre-molars are fully functional teeth in humans used for chewing and grinding food. Therefore, they are not vestigial organs.

Answer: Pre-molars