There are number of organs present in the body which are are not used in any activity by the body. They were useful only for certain period . Such organs are called vestigial organs.
example: digestive system - appendix
                 eye - third eye/nictitating membrane

1.during the course of evolution,some organs remain in organisms.for example,ependix in digestive system human beings it has no role to play in process of digestion
3.but in herbivores like rabbit appendix plays an important role
4.such type of organs which are not useful in animal are called vestigial organs
5.there are nearly 18 vestegial organs in human beings
6.for example pinna,hair on skin,mammary glands in man,etc
7.that's why human being is said to be a moving museum of vestigial organs.
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