You are presented with the quiz "What from burning coal and oil dissolving in water in the atmosphere causes acid rain?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "gases from burning coal and oil dissolving in water in the atmosphere causes acid rain" and "helpful Generalizations Vapors and gases are molecules". 

So, what's the best answer to the question?


 

       vapors    