Additional muscles in the ...... impact the ability of humans to increase the strength of inspiration and expiration. Complete the given $NCERT$ statement with an appropriate option.

During respiration,if the volume of the thoracic cavity of a rabbit is maximum,then:

Expiration occurs due to

In the expiration condition,the diaphragm becomes

Name the important parts involved in creating a pressure gradient between the lungs and the atmosphere during normal respiration.

$A$: 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.