What is the ultimate source of energy in traditional plants powered by fossil fuels?

Question

jhannybean · Answer

It's the same source of energy for providing light on our planet, helping flowers bloom, and keeping us happy. Haha,

jhannybean · Answer

it rises in the east and sets in the west.

nincompoop · Answer

traditional plants powered by fossil fuels? huh? 
if they are being powered by fossil fuels, then I don't know what else are you looking for as a source for energy. 

I think this question is not properly phrased.  

if you meant traditional plants, then you might be referring to photoautotrophs, which gives you the clue that it probably has something to do with "photo" or light.