Question

write in one word
Small bag like structures in which air
goes in and out​

Answer 1

Answer:

alveoli

Explanation:

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

Answer 2

Answer:

Alveoli in lungs

I hope it will help you.