Which of the following is an example of an organic fuel?

Wood is classified as an organic fuel because it is derived from living organisms, specifically trees and plants. Organic fuels consist of carbon-based materials that originate from biological sources. In the case of wood, it is the result of the photosynthesis process, where trees convert sunlight into energy, storing carbon in their structure.

Coal and natural gas are also carbon-based fuels; however, they are not classified as organic fuels in the same sense as wood. Coal is considered a fossil fuel, formed over millions of years from the remains of ancient plants and organisms, and natural gas, primarily composed of methane, is also a fossil fuel that forms from decomposed organic matter under heat and pressure over long geological timeframes.

Metals, on the other hand, are inorganic materials and do not fall under the classification of fuels at all as they do not burn to release energy in the same manner that organic fuels do. Thus, wood stands out as the correct example of an organic fuel based on its origin and composition.