| A | B |
|---|
| when water in the cracks of rocks freezes and expands | ice |
| when a rock or element wears or breaks down | abrasion |
| when sand blows against rock and the rock is shaped differently | wind |
| the water moves against rocks and changes their shapes | water |
| when rocks fall on one another and wear down | gravity |
| water gets in roots of plants and make them bigger | plants |
| animals burrow in the ground | animals |
| when it rains the acids come down and harm plants | acid precipitation |
| an acid eats away rock and makes different shapes | acids in ground water |
| acids break down rocks that are called lichens | acids in living things |
| acids that can eat away iron and make it rust | air |
