(i)An essential part of the body is the lungs. The passage within the lungs separates into successively smaller tubes that ultimately come to an end in balloon-like structures known as alveoli.
(ii)The surface provided by the alveoli allows for the exchange of gases. Typically, a dense network of blood arteries can be found inside the alveoli\’s walls. We are aware that when we breathe in, the chest cavity enlarges and our ribs are lifted.
(iii)Air is drawn into the lungs as a result of this action, filling the expanded alveoli.
(iv)The blood transports the necessary carbon dioxide from the rest of the body and provides it to the alveoli; the blood also absorbs the oxygen from the alveolar air.