Which of the following is NOT an element of burning?

Burning, also known as combustion, requires specific elements to occur. The essential components of this chemical reaction are fuel, oxygen, and heat.

Fuel serves as the material that burns, providing the necessary energy source. Oxygen is essential, as it is the oxidizing agent that supports the combustion process. Heat is also a critical component because it initiates the combustion reaction by raising the temperature of the fuel to its ignition point, allowing the reaction to sustain itself.

Smoke, however, is a byproduct of burning rather than a fundamental requirement. While smoke may be produced during the combustion process, it is not necessary to achieve the act of burning itself. Therefore, it is correct to identify it as not being an element of burning. This distinction highlights the difference between the actual components that facilitate combustion and the resulting products of that reaction.