Answer: Mountains do not last forever. They don't last forever because of weathering and erosion.
Answer: One way solid rock can break into smaller pieces naturally is by ice. This means that water freezes and breaks the stone. Another way solid rock can break into smaller pieces naturally is by tree roots. This means that tree roots can break stone.
Answer: Rocks at the top of a mountain are sharp and jagged, whereas rocks at the bottom of a mountain are round. The rocks at the bottom become this way by erosion. Our demonstration showed us that by the sugar bumped into each other and became roundish.