Question

Select correct answer and give reasons-During inspiration air passes into lungs due to
a). Increased volume of thoracic cavity
b). Fall in pressure inside the lungs
c). Increase in the volume of thoracic cavity and fall in lung pressure.
d). Muscular expansion of lungs

Answer 1

Ans is (c)
Increase in the volume of thoracic cavity and fall in lung pressure.

Answer 2

during inspiration...the air gets inhaled in lungs not because of muscles.... because if it can be possible then one can hold his breathing for a long time......so it's answer should be C because as the total air pressure inside the lungs decreases...the lungs maintain their pressure application by intaking more air from outside......as the pressure decreases the lungs swell up i.e. their volume increases to make a space for more air in it