Question

What do u mean by the residual volume of air in lungs??

Answer 1

they r bcoz of alveoli when v breath  alveoli pumps because they r balloon  like structures

Answer 2

$\huge\mathfrak\red{Heya\:Mate}$

$\huge{\boxed{\bold{ANSWER}}}$

During the breathing cycle, when air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbondioxide to be released.

$\large{\bold{HOPE \:IT \:HELPS \:YOU!!!}}$