Question

why
Alveoli's structure
is balloon like​

Answer 1

Answer:

Alveoli are tiny balloon shaped structures and are the smallest passageway in the respiratory system. The alveoli are very thin, allowing the relatively easy passage of oxygen and carbon dioxide (CO2) between the alveoli and blood vessels called capillaries.

Answer 2

Answer:

Alveoli are extremely thin-walled and richly supplied with blood capillaries. The balloon-like shape of alveoli allow for the maximum surface area for the exchange of gases. This is so that when air enters the alveoli, the exchange of $CO_{2}$ and $O_{2}$ between each alveolus and the blood vessels happens in the most efficient way possible.

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