Which chemical element is the only oxidizer that can result in a fire when combined with fuel and ignition source?

The only oxidizer that can cause a fire when combined with fuel and an ignition source is oxygen. Oxygen plays a critical role in the combustion process, as it is the element that supports and facilitates the chemical reaction between a fuel and an ignition source. When oxygen is present in sufficient quantities, it reacts with combustible materials, allowing a fire to ignite and sustain.

In typical combustion reactions, oxygen combines with a variety of fuels – such as hydrocarbons, wood, or other flammable materials – to produce heat, light, water vapor, and carbon dioxide as byproducts. This is why oxygen is essential in any fire scenario; without it, a fire cannot occur.

Other options do not possess the characteristics of an oxidizer in the same way. Hydrogen, although flammable, does not act as an oxidizer in combustion processes. Carbon dioxide is actually an asphyxiant and acts to suppress combustion, not promote it. Nitrogen, while abundant in the air, is largely inert and does not support combustion either. Thus, it is oxygen that uniquely fulfills the requirement as the oxidizer necessary for producing fire in the given context.