Carbonic acid dissolves limestone and other rocks. This is an example of chemical erosion. An example is in the caves. Caves are formed where rainwater as it falls through the atmosphere absorbs carbon dioxide. The carbon dioxide makes the rain acidic to react it with the limestone bedrock. The rainwater is absorbed by the soil into the ground. Then as it enters through the soil, the rainwater will absorb more carbon dioxide that is produced by the decomposers. The carbon dioxide with water reacts to form carbonic acid. The carbonic acid will react to limestone and dissolves it slowly. As the space become larger, water can enter into it.