In frogs eyelids are
A) Functional
B) Non- functional
C) Absent
D) None of the above

Hint:Frogs use their regular set of eyelids to keep their eyes moist and clean. They have a bottom lid that stays still and an upper lid that blinks.

Complete answer :
Frog has eyes and like many other organisms, they have eyelids, both an upper and a lower one. If we talk about eyelids, eyelids are the fold of the skin, which are present on the upper surface of the eyes and the lower surface of the eyes. Different organisms have different shapes and sizes of the eyelids. Reason being different organisms have different kinds of eyes. Some animals do not have eyelids; it depends on which function eyelids will play and what will be its importance. However, the main function of eyelids is that it protects and covers the eyes. Therefore, if an organism has eyelids it there is a very high possibility that it has some important role. Eyes, anyway, are very delicate organs and hence, need protection. That’s the reason eyes are generally watery to remove any kind of dirt or substance. The eye contains muscles that retract eyelids to open and close. Talking about frogs, the upper eyelid is a simple skin fold. It is a thin muscular membrane that is translucent and movable; it rises from the lower edge of the eye to protect and cleanse the eye. When a frog's eyeball is retracted into the eye socket the lower lid spreads over its surface. And hence, eyelids of a frog are functional.

Hence the correct answer is option ‘A’ i.e functional.

Note: Frog has both upper and lower eyelid. Both the eyelids are functional as both upper and lower eyelids are protecting and supports the eyes like eyelids of any other organism.