Question

The upper eyelids of the frog is
A) Thick
B) Thin
C) Absent
D) None of these

Answer 1

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:
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 that 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. 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. Therefore, the upper eyelid of the frog cannot be thick. Otherwise, it will create difficulty in the movement.
Hence, option (a) is wrong and surely eyelids are not absent, therefore, option (c) is also wrong.

The correct answer is option (b), as the upper eyelids of the frog are thin. Frog has eyes and like many other organisms, they have eyelids, both an upper and a lower one.

Note: The lower lid of the frog’s eyeball is a translucent membrane. When a frog's eyeball is retracted into the eye socket the lower lid spreads over its surface. Hence, it cannot be thin.