Fact 1: Most canyons are formed by flowing rivers through erosion over long periods of time. Fact 2: Canyon formed as a consequence of river erosion. Given the two facts above, what does erosion form?

Pick from: 1. valleys 2. Sediment 3. mountains 4. canyons 5. soils 6. hills 7. soft soil 8. loose soil
The answer is:
4.