Answer :
Final answer:
Condensation of water vapor from warm, exhaled air creates the fog effect on a mirror when breathed upon.
Explanation:
Condensation occurs when warm, moist air cools, causing water vapor to transition into liquid water droplets. When you breathe out warm, moisture-laden air on a cold surface like a mirror, the sudden temperature change causes the water vapor to condense into tiny droplets, creating the 'fog' you see. This process is similar to how clouds form in the atmosphere.
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