Valleys are typically formed through different processes such as erosion and tectonic activity. Erosion occurs when water, ice, or wind wear away the land, creating a valley. Tectonic activity, on the other hand, involves the movement of the Earth's crust, which can create mountain ranges through processes like folding and faulting. These processes can cause the crust to uplift and push together, resulting in the formation of mountains. It is important to rephrase this information using your own words and ensure to run it through a plagiarism checker to avoid any plagiarism concerns.
