Question

what does acid deposition most commonly occur as?
rain, snow, or fog
drought conditions
volcanic ash
dust storms

Explanation:

Acid deposition, commonly known as acid rain, includes wet deposition forms like rain, snow, or fog (also called acid precipitation) as these are ways acidic compounds (from air pollution) fall to the ground. Drought is a lack of precipitation, volcanic ash is from eruptions (not typical acid deposition), and dust storms are about particulate matter, not acid deposition.

Answer:

A. rain, snow, or fog