Question

lungs always contain a residual volume of air. give reason

Answer 1

The lungs always contain a residual volume of air so that during breathing cycle there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released. Residual Volume is important because it prevents the lungs from collapsing.

Answer 2

Lungs contain a residual volume of air because;

• Residual volume of air is the air remaining in the lungs after a complete exhalation.
• There is always some amount of air left in the lungs however much we exhale.
• Lungs can never be devoid of air.  
• Residual volume of air is important to stop the lung tissues from sticking together.
• It is also important to maintain the volume of the respiratory gases; oxygen and carbon dioxide.