Scientists in China are studying acid rain. They notice a significantly higher degree of acid rain in areas close to factories. During which physical process would this pollution occur?

Acid rain forms when factory pollutants enter the air and mix with water vapor, then return to the ground in precipitation. Precipitation is part of the water cycle, so the pollution occurs through the water cycle. Plate tectonics, soil building, and erosion do not describe this movement of pollutants through the atmosphere and rain.

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