Final answer:
Carbon dioxide, as a fire extinguisher, extinguishes fires by suffocating the flames through the displacement of oxygen.
Step-by-step explanation:
Carbon dioxide, as a fire extinguisher, is an inert gas that produces a white cloud on discharge and acts to extinguish fires by suffocating the flames. When carbon dioxide is discharged from a fire extinguisher, it displaces oxygen in the air, which is necessary for combustion, thereby cutting off the supply of oxygen to the fire. As a result, the fire is starved of oxygen and is extinguished.