The following figure shows a cross-section of the cochlea. Identify the canals labeled $P$,$Q$,and $R$.

The membranous labyrinth is enclosed in the:

Arrange the following events in a correct order that lead to the formation of an auditory impulse in human ears from the codes given below:
$I.$ Vibration is transferred from the malleus to the incus and then to stapes
$II.$ Basilar membrane moves up and down
$III.$ Nerve impulse is transmitted by cochlear nerve to auditory cortex of brain for impulse analysis and recognition
$IV.$ Sound waves pass through ear canal
$V.$ Stereocilia of hair cells of organ of Corti rub against tectorial membrane
$VI.$ Sound waves cause ear drum to vibrate
$VII.$ Nerve impulse is generated
$VIII.$ Vibrations move from fluid of vestibular canal to the fluid of tympanic canal
$IX.$ Membrane at oval window vibrates

Our ear can hear the frequency of sound waves in the range of:

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

The bony labyrinth is filled with