Question

which statement explains how smog forms?
○ volcanoes erupt and release ash into the sky.
○ strong storms pick up soil and mix it with fog.
○ sunlight and heat react with gases in the atmosphere.
○ gases move high into the atmosphere and then fall to earth in rain.

Explanation:

Smog, specifically photochemical smog, forms when sunlight and heat trigger chemical reactions with pollutants (like nitrogen oxides and volatile organic compounds) in the atmosphere. Volcanic ash is volcanic haze, storm-lifted soil is dust fog, and gas deposition in rain is acid rain, not smog formation.

Answer:

Sunlight and heat react with gases in the atmosphere.