Answer: no other source
Explanation:
The Earth gets energy from the sun which includes both heat and light and these are necessary for chemical reaction.
When the energy from the Sun gets to the Earth, they come as solar radiation and included in such solar radiation are infrared, invisible light, X-rays, ultraviolet light, radio waves, and gamma rays.
We should note that no other source is required for the Earth to get energy. The sun supplies it its energy.