Question

Which best describes how air moves during convection?
A) cool air falls down
B) warm air falls down
C) cool air is replaced by warm air
D) air always falls down

Answer 1

the correct answer is option A

Answer 2

The correct answer is option A) cool air falls down.

In convection, hot air rises from the Earth's surface and becomes cold at higher altitude because of lower temperature there. As it cools, it sinks down to the surface of the Earth. On reaching Earth, it warms again and rises up again. The main reason for this phenomenon is - sinking cold air pushes the warm air up.

Option B) and C) are absolutely wrong and hence eliminated.

Option C) cool air is replaced by warm air- This is wrong, in fact the opposite is correct as you can see from the above explanation.