Question

why are lungs made up of millions of alveoli?

Answer 1

Hey mate _

Alveoli are present in lungs in millions of number ,as their walls are made up of squamous epithelium,they can easily do gaseous exchange through their walls,so for the requirement of gas exchange [CO2 and O2] , they are present in lungs .

Hope it helps _

Answer 2

The lungs are made up of several ,that is, millions of alveoli because they are all covered with capillaries, which is where the oxygen gets into the blood.