Define the following terms:
$(1)$ Inspiration
$(2)$ Expiration

Given below are events occurring during inspiration. Select the correct order of sequence from the options given below.
$(I)$ Air from atmosphere rushes into lungs.
$(II)$ Thoracic volume increases.
$(III)$ Intercostal muscles contract and ribs along with sternum move upward and outward.
$(IV)$ Diaphragm becomes flat and goes downwards.

Hiccups are caused by the activity of which of the following?

When do the expiratory muscles contract?

Arrange the given steps of expiration in the sequence of events occurring first:
$I.$ Relaxation of the diaphragm and sternum
$II.$ Reduction of the pulmonary volume
$III.$ Expulsion of air from the lungs
$IV.$ Increase in intra-pulmonary pressure
Choose the correct option.

Which muscles help us to increase the strength of inspiration and expiration?