Acid rain is caused by a chemical reaction, due to when the two compounds sulfur dioxide and nitrogen are released into the air. Therefore, the answer is 4!
Please make as brainliest if I helped you
They dig or "mine" for it. just like they do coal
<h2><em>In general, a scientific law is the description of an observed phenomenon. It doesn't explain why the phenomenon exists or what causes it. The explanation of a phenomenon is called a scientific theory. It is a misconception that theories turn into laws with enough research</em></h2>