Question

Why we crawl on a floor if the room is filled with smoke??

Answer 1

Because smoke being lighter than air usually levitates above the ground, unless the room is teeny tiny.

We crawl down so that we may not inhale any harmful gases present in smoke

Answer 2

we crawl on the floor because the smoke floats up. and the air below is fresher which helps in breathing
this is because smoke is lighter than air

p.s not copied