🔍 Key Concepts

• Fire tetrahedron and how it differs from the older fire triangle • Role of oxidizing agent in sustaining combustion • Why normal atmospheric air supports fire

💭 Think About

• Which of these choices is the common oxidizer present in the air that allows most fires to keep burning? • Do fires normally produce carbon monoxide or carbon dioxide as a result of burning, or do they need them to start and sustain the burning? • Is "any gaseous substance" enough to support fire, or must it be a specific type of gas with certain properties?

✅ Before You Answer

• Identify which option is an oxidizer required for combustion, not a by‑product of it • Eliminate any choice that is typically a product of incomplete or complete combustion rather than a necessary component • Ask yourself: which gas do firefighters and fire-prevention materials always talk about when explaining how fire is supported or smothered?