It is simply changed from one form to another, etc., etc.] a.) backward : electricity ---> mechanical energy of turbine ---> heat energy of steam ---> chemical energy of burning coal ---> photosynthetic energy from the sun that grew the original trees ---> the sun's energy.
(It; is simply changed backward; from one form to another, etc.) (the sun; grew; the original trees)
It the sun
is simply changed backward grew
from one form to another, etc.
the original trees