What three things are needed for combustion to occur?

For combustion to occur, the essential elements are heat, oxygen, and fuel.

Heat is required to raise the temperature of the fuel to its ignition point, enabling the combustion process to start. Oxygen, typically from the air, serves as the oxidizing agent that supports the chemical reaction involved in combustion. Fuel is the material that burns, providing the energy that is released during the reaction. Without any one of these three elements, combustion cannot take place, making them indispensable for the process.

While other combinations of elements may be necessary for different chemical reactions or conditions, they do not encompass the fundamental requirements for combustion. Moisture can inhibit combustion, while pressure, while relevant in some contexts, is not a direct necessity like heat, oxygen, and fuel are.