What is the cause of altitude sickness?

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.

$A$: Normal expiration during quiet breathing,unlike inspiration,is a passive process because no muscular contractions are involved.
$R$: Normal expiration results from the elastic recoil of the chest wall and lungs.

Exhalation is the process of expulsion of air through the respiratory tract. Which of the following figures illustrates the process of exhalation?

State whether the given statements are true or false.
$I.$ Ventilation in humans is an active process.
$II.$ Diaphragm helps in generating the pressure gradient in the lungs.
Choose the correct option.

Inspiration occurs when intra-pulmonary pressure is