Earth's mountains form and erode from erupting and by shifting plates.
Wind, Water, Waves, Glacier (Ice), and Ocean currents.
Yes;because rocks erodes and rock are there.
100,000 years or more depending on the size
As glaciers move over any earth surface, they carry rocks, stones and boulders with them. These are at the bottom of the glacier under very high pressures. As the glacier moves it is this carried...