Pick your answer from:
a). energy;
b). carbon;
c). heat;
d). earthquakes;
e). air;
f). oil;
g). O2;
h). water;
Given those answer options, answer the question: Fact 1: Burning wood is used to produce heat. Fact 2: Combustion-related, motor vehicles, wood burning, open burning, industrial processes. Given the two facts above, combustion is used to produce what?
A:
c).