Question

The reduced nictitating membrane is an example of

• A. Homologous organ
• B. Vestigial organ
• C. Analogous organ
• D. Functioning organ

Answer 1

The correct option is B Vestigial organ

The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it, while maintaining visibility. Some reptiles, birds, and sharks have full nictitating membranes; in many mammals, a small, vestigial portion of the membrane remains in the corner of the eye. Some mammals, such as camels, polar bears, seals and aardvarks, have full nictitating membranes. Often called a third eyelid. Thus, option B is correct.
Analogous organs are those that perform similar functions but have entirely different embryonic origins. Nictitating membrane is not example of analogous organs. Thus, option C is wrong.
The structure, which are similar in their morphology, anatomy, genetics and embryology but dissimilar in their function are called as, homologous organs. Nictitating membrane is not example of homologous organs. Thus, option A is wrong.
Nictitating membrane is not functional in all organisms. So, it is not an example of functioning organ. Thus, option D is wrong.