Which of the following is considered a source of energy?

Fire, particularly when derived from biomass, is considered a source of energy because it releases heat and light when materials such as wood, crop waste, or other organic matter are burned. This energy can be harnessed for various purposes, including cooking, heating, and generating electricity. Biomass is a renewable resource, as it can be replenished through natural processes as plants grow, absorbing sunlight and carbon dioxide.

In contrast, cold air does not provide energy; rather, it is characterized by a lack of heat. Sandy soil serves as a substrate for plant growth but does not itself provide energy; instead, it holds water and nutrients necessary for plant life. Moonlight, while it provides illumination, is merely reflected sunlight and not a source of energy in a usable form for activities like heating or powering devices. Therefore, fire from biomass stands out as the only option that directly transforms matter into usable energy through combustion.