Fact 1: The emission of sulfur dioxide causes acid rain.

Fact 2: Sulfur in the coal becomes sulfur dioxide when burned.

Given the two facts above, answer the question "Acid rain can be a result of:" with the following options: 
- burning
 - citric acid
 - flow of electrons
 - fashion
 - acid wash
 - chemical changes
 - burning coal
 - Pollution


 

       burning coal  