What describes the process of combustion?

The process of combustion is characterized as a rapid chemical reaction that occurs between a fuel and an oxidizer, predominantly oxygen. This reaction generates heat and light, which are the hallmark signs of combustion. When a fuel burns, it transforms into combustion products, releasing energy in the form of heat and often visible light, such as flames. This combination of factors makes option A the most accurate description of combustion.

In contrast, other options present incorrect or incomplete descriptions. For example, a slow chemical reaction that produces no light is not representative of combustion since combustion is inherently a rapid and energetically drastic process. The breakdown of organic material by heat does not accurately capture the essence of combustion, as it refers more to processes like pyrolysis rather than combustion itself. The last option, which refers to gas release without heat production, fundamentally neglects the defining characteristics of combustion, where heat is a critical component of the energy release. Thus, option A stands out as the correct definition of the combustion process.