Question

when the air expand, it​

Answer 1

So air, like most other substances, expands when heated and contracts when cooled. Because there is more space between the molecules, the air is less dense than the surrounding matter and the hot air floats upward. This is the concept used in the hot air balloons.

Answer 2

Answer:

air don't not expand It spreads because our earth contains lots of gasses so air means o2 cannot expand it spreads