Which of these describes a divergent boundary?
a) two plates moving away from each other and forming a rift valley
b) two oceanic plates rubbing against each other, forming a mid-ocean ridge
c) two continental plates colliding, forming a mountain range
d) two oceanic plates colliding, forming a volcanic arc

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.