Which of the following is a necessary component for combustion?

Oxygen is a necessary component for combustion because it supports the chemical reaction that occurs during the burning process. Combustion is an exothermic reaction, meaning it releases heat, and for it to happen, fuel must combine with an oxidizer, which is typically oxygen in the atmosphere.

When a material is heated to its ignition temperature in the presence of sufficient oxygen, it ignites and combusts. This is the fundamental principle behind fire: the presence of oxygen allows the fuel to react chemically, resulting in fire. Without sufficient oxygen, combustion cannot occur, leading to the extinguishment of flames, which is why fire suppression often involves cutting off the oxygen supply.

In contrast, water, carbon dioxide, and smoke do not play a direct role in the combustion process. Water can act as a fire suppressant because it cools the flames and reduces the available oxygen, while carbon dioxide is often a byproduct of combustion and can also be used to suffocate flames. Smoke is an indicator of combustion occurring but does not contribute to the reaction itself. Therefore, oxygen is the critical element required for combustion to take place.