The answer SHOULD be D, if I'm wrong, I really am sorry.
Many factors, both natural and human, can cause changes in Earth's energy balance, including: Variations in the sun's energy reaching Earth. Changes in the reflectivity of Earth's atmosphere and surface. And Changes in the greenhouse effect, which affects the amount of heat retained by Earth's atmosphere.
Answer:
The two natural factors are.
Rainfall and river
The two man made factors are
Canal and tube wells
Death rate, infant mortality
A—A because we can use technology to our advantages