Which sequence correctly represents the ABCs of basic life support for adults?

• A. Airway, Circulation, Breathing
• B. Airway, Breathing, Circulation
• C. Breathing, Airway, Circulation
• D. Circulation, Airway, Breathing

Answer: (B)

The sequence tested emphasizes the order of steps in basic life support: airway, breathing, then circulation. Opening the airway is the first priority because, if the airway is blocked or not open, any breaths you give won’t reach the lungs. Once the airway is open, you assess and provide breathing as needed so oxygen can actually enter the lungs. Only after ensuring the airway and breathing are addressed do you turn to circulation, using chest compressions to keep blood flowing to the heart and brain if there’s no pulse. This order makes sense because each step enables the next: you can’t ventilate effectively without a clear airway, and you can’t sustain oxygen delivery without circulation.