Complete the paragraph.
Earth's surface is made mostly of rock. Water, wind, and ice can break down this rock to form ().
melted rock loose pieces bigger pieces
Water, wind, and ice can break down rock into loose pieces. This breakdown of rock is called weathering. Here are some ways that weathering can happen.
Water crashes into a rock. Over time, the rock starts breaking down into smaller pieces.
Wind blows grains of sand into a rock. As the sand hits the rock, small pieces break off from the rock.
Water flows into a crack in a rock. On a cold night, the water freezes to form ice. As the water freezes, it takes up more space. This makes the crack bigger. Over time, the crack becomes big enough to break the rock into smaller pieces.