Question

which process causes earths surface to warm?
the conduction of heat by air above earths surface
the radiation of the suns electromagnetic waves
the convection of warm air from the atmosphere
the reflection of electromagnetic waves off bodies of water

Explanation:

The Sun emits electromagnetic waves (including infrared, visible light, etc.). These waves travel through space and reach Earth. When they hit Earth's surface, the surface absorbs the energy from these waves, which causes the surface to warm. Conduction by air (air is a poor conductor), convection of warm air (this is heat transfer within the atmosphere after the surface is already warm), and reflection off water (which would not warm the surface as it's reflecting energy away) are not the main processes for initial warming of Earth's surface.

Answer:

the radiation of the Sun's electromagnetic waves