The sequence of ear ossicles from outside to inside is

$.....P.....$ ends at the oval window,while $.....Q.....$ ends at the round window,which opens to the middle ear.
$\quad\quad\quad P\quad\quad \quad Q$

Otoconium is found in

The true sense of equilibrium in mammals is situated in the:

The lower membrane of the $scala$ $vestibuli$ is the:

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.