In mammals,what has developed as the external ear?

Hearing in $rabbit$ is better than $frog$. One reason for this is that $rabbit$ has

Which of the following sensory organs is responsible for maintaining the balance of a frog's body?

Choose the correct option for the tympanic membrane.

The bone that is in contact with the oval window is:

Read the following statements regarding the structure of the human ear and select the correct option.
Statement $I$: The tympanic membrane is covered with mucous membrane on the inner side,to the surface of which is attached the $1^{\text{st}}$ ear ossicle,namely the incus.
Statement $II$: Scala vestibuli and scala tympani are filled with perilymph and form a part of the cochlea.