Infrared radiation - Greenhouse gases in the atmosphere absorb most of the earth's emitted infrared radiation which heats the lower atmosphere
I think it is B. Sorry if I’m wrong
Yes you're correct. For distance, SI is based on meters.
D
Because if an object is moving at a constant speed the force of friction must equal the applied (horizontal) force, and for it to be accelerating or decelerating, the force of friction and the applied force must be unequal