Question

Circulation of air removes stale air and brings in fresh air

Answer 1

Answer:

Replacement of stale inside air with fresh outside air is called ventilation. Ventilation can occur naturally, aided by the stack effect and open windows, or mechanically, with the use of a fan, or series of fans, that pull air in or out of the house.

Explanation:

please mark as brainlist

Answer 2

Answer:

the warm air is always lighter than the cold air.

Explanation:

take an example of candle.

light the candle, than you observe it carefully. you will notice that the warm air goes up and the cold air replace the warm air because the air molecules dash with the fire and the air molecules become warm, as I told warm air is always lighter that cold air.