Question

Hearing in rabbit is better than frog; one reason for this is that rabbit has
A) Three semicircular canals
B) Vibratile tympanic membrane
C) Movable pinna
D) Both fenestra ovalis and Eustachian tubes

Answer 1

Hint:- For most animals ears play two very important roles- they aid in hearing and they maintain body balance. Animals in the wild can detect predators and save themselves from being prey. Most organisms have these fluid-filled semicircular canals that help balance the body. Usually, the ear has three parts- external, middle, and inner. In some animals the external ear is absent.

Complete answer:
Frog is an amphibian and can hear in water as well as on land. Unlike most animals frogs do not have an external ear or pinna. Its tympanic membrane vibrates canses any noise and conducts those vibrations to the middle and inner ear. The middle ear of the frog has one ossicle called columella Auris that conducts the vibration to the inner ear. The Eustachian tube maintains the equilibrium in the ears while the frog is swimming. The inner ear has the semicircular canals and the lagena that aids in hearing.
In the case of rabbits, all three parts- outer, middle, and inner are present. The longer the pinna (external ear) the easier it is for the rabbit to detect sounds. Rabbits with shorter ears can only hear the predator when it is closer to it. Their hearing is much sharper than humans. The muscles in the pinna are developed enough to allow movement. Therefore they are able to collect sound from all directions and channel it to the middle and inner ears. The tympanic membrane starts to vibrate and sound is conducted to the ossicles and from the ossicles, it moves to the inner ear. In the inner ear, semicircular canals and cochlea are present. Cochlea aids in hearing.
It is the movable pinna that makes rabbits hearing better.

The correct option is (C).

Note:- The external ear of the rabbit also helps in thermoregulation. When the temperature is quite high the rabbit extends its ears, this way it cools down. The larger surface area of the ears allows the body to lose heat. It holds the ear closer to the body to conserve heat when temperatures are low.