Acid rain is a way to call acid falling down from the atmosphere. Acid rain occurs when it mixes up with water, oxygen, and other chemicals. There are two types of acid rain which are either wet or dry. Wet means rain, fog, or snow and it effects most plants and animals. Dry may mean different particles which, if the wind blows these particles they can effect homes, buildings, and cars.
In the image to the left you can see how acid rain is formed and the damage it causes. Many lakes, streams, and rivers, which play a huge role in the environment are damaged due to acid rain. This proceeds to effect the animal life around those areas ultimately effecting the environment.