Answer:
1) Visible light reflected by clouds
2) Infrared light emitted by the surface and atmosphere
3) Reflection of visible light by the surface
Explanation:
The primary source of heat for the Earth is Sun. The heat is transferred in the form of light from the Sun.
Now, for the Earth to maintain nearly the same temperature some amount of this light must be returned.
The heat or the energy is returned by the Earth through
1) Visible light reflected by clouds
2) Infrared light emitted by the surface and atmosphere
3) Reflection of visible light by the surface