Which statement about combustion is true?

Which statement about combustion is true?

• A. Fire continues to burn if fuel is removed.
• B. Fire can be extinguished by removing heat only.
• C. Fire will extinguish if either fuel, oxygen, or heat is removed.
• D. Fire requires all three elements to be present to keep burning.

Answer: (C)

Combustion needs three ingredients: heat to reach ignition, fuel to feed the reaction, and oxygen to sustain it. This is why removing any one of these elements stops the flame. If the fuel source is cut off, the fire has nothing to burn and dies. If you restrict oxygen—smothering or isolating the fire—the reaction can no longer continue. If you cool the area below the ignition temperature, the fuel no longer reaches the point where it will burn. So, extinguishing happens when any one of these elements is removed, which is why the statement stating fire will extinguish if either fuel, oxygen, or heat is removed is true. The other ideas don’t hold in all cases. Removing fuel alone stops burning, but there are situations where a flame might persist briefly if heat or oxygen are still present. Removing heat alone isn’t a universal extinguisher because fuel and oxygen can remain and keep the reaction possible. And fires don’t require all three elements to be present at all times—if one is removed, the flame generally cannot continue.

Combustion needs three ingredients: heat to reach ignition, fuel to feed the reaction, and oxygen to sustain it. This is why removing any one of these elements stops the flame. If the fuel source is cut off, the fire has nothing to burn and dies. If you restrict oxygen—smothering or isolating the fire—the reaction can no longer continue. If you cool the area below the ignition temperature, the fuel no longer reaches the point where it will burn. So, extinguishing happens when any one of these elements is removed, which is why the statement stating fire will extinguish if either fuel, oxygen, or heat is removed is true.

The other ideas don’t hold in all cases. Removing fuel alone stops burning, but there are situations where a flame might persist briefly if heat or oxygen are still present. Removing heat alone isn’t a universal extinguisher because fuel and oxygen can remain and keep the reaction possible. And fires don’t require all three elements to be present at all times—if one is removed, the flame generally cannot continue.