Valleys and mountain ranges form through the process of tectonic activity. When tectonic plates collide or separate, they can create a variety of landforms. Mountains are formed when two plates collide and force the earth's crust to buckle and fold, resulting in upward movement and the formation of a mountain range. Valleys, on the other hand, can be formed through different processes, including erosion by rivers, glaciers, or tectonic activity that causes the land to sink and create a depression. Overall, the formation of valleys and mountain ranges is a complex process influenced by geological forces and erosion.
