Question

In frog, the upper eyelid is
a. Absent
b. Slightly movable
c. Rapidly movable
d. Immovable

Answer 1

Hint: Frog is an amphibious animal found in and near the fresh water bodies. They are mostly seen during the rainy season as it is their breeding season.

Complete answer:
- Frog is a carnivorous animal that swims in water and leaps on land. It has a dorsoventrally flattened body. It is spotted olive green on the dorsal side with irregular dark spots and pale yellow color on the ventral side. Dorsal side has a median and longitudinal dorsal line running from head to posterior end of the body. It is bilateral symmetrical.
- Frog has two body parts- head and trunk.
- Head is flattened and triangular. It is produced into a conical snout in front of nostrils and has following structures- mouth, nostril, eyes, brow spot, tympanic membrane, and vocal sacs.
- The eyes of frogs are large-sized and spherical and are located on the dorsolateral sides of the head. They bulge outwards to see around even in the absence of a neck. Each eye is with three eyelids. The bottom eyelid is immovable, the upper eyelid is slightly movable and the third eyelid or nictitating membrane protects the cornea from dust on land and mud in the pond or during hibernation.
- The trunk of the frog has thorax, abdomen and limbs.

Hence, the correct answer is option (B).

Note: It is a cold-blooded or poikilothermic animal that undergoes hibernation or winter sleep as well as aestivation as well as summer sleep. During these periods it depends upon the reserve food stored in its body and respires through skin and has a low metabolic rate.