Here's why:

* Chemical weathering involves the breakdown of rocks and minerals through chemical reactions.

* Acid precipitation is rain, snow, sleet, or hail that has a higher acidity than normal due to the presence of pollutants like sulfur dioxide and nitrogen oxides.

* When acid precipitation comes into contact with rocks and minerals, it can react with them, causing them to dissolve or break down into smaller particles.

For example, acid rain can react with calcium carbonate in limestone, causing it to dissolve and form caves.