Which item contains oxygen and is associated with promoting combustion?

• A. Water; fuels fire
• B. Air; fuels fire
• C. Aluminum; fuels fire
• D. Charcoal; fuels fire

Answer: (B)

The key idea is the substance that provides the oxygen needed for burning. Combustion needs an oxidizer, heat, and fuel, and the oxidizer in most fires is oxygen gas from the surrounding air. Air supplies this oxygen so flames can continue to burn when fuel is present.

Water contains oxygen, but it doesn’t act as an oxidizer to promote burning. Instead, it absorbs heat and can smother a flame, helping to stop combustion. Aluminum isn’t something that supplies oxygen to sustain burning in ordinary conditions; it forms a protective oxide layer that actually resists further oxidation. Charcoal is a fuel, not an oxidizer, so while it burns in air, it doesn’t contain oxygen to promote the reaction itself.

So the option that contains oxygen and is associated with promoting combustion is air, since it provides the oxygen necessary for burning.