Final answer:
The described combustion reaction, combining fuel with O2 to create CO2 and H2O, is exothermic, releasing energy as heat and light.
Step-by-step explanation:
The combustion reaction described, where fuel combines with O2 to produce CO2 and H2O, is an exothermic process. This means that the reaction releases energy, typically in the form of light and heat, as the bonds in the fuel and oxygen molecules break and new bonds form to create carbon dioxide and water. Combustion reactions are commonly used in everyday life, such as the burning of methane in kitchen stoves, to release energy that can be harnessed for various purposes.