Lung ventilation movements are due to

Pick the correct statement.

Air moves into the lungs when

On an average,a healthy human breathes $......$ times per minute.

The diagram above shows which phenomenon of respiration?

Arrange the given steps by which the lungs show inspiration,in the sequence of events occurring first:
$I.$ Increase in the volume of the thoracic chamber in the dorsoventral axis
$II.$ Upward and outward movement of the ribs
$III.$ Contraction of intercostal muscles
$IV.$ Entry of air inside the lungs
$V.$ Contraction of the diaphragm
$VI.$ Increase in the volume of the thoracic chamber in the anteroposterior axis
Choose the correct option.