What type of mountains exhibits flattened rolling peaks and wide valleys?

The type of mountains that exhibit flattened rolling peaks and wide valleys are called "plateau mountains." These mountains are typically formed through geological processes such as erosion and uplift, which create broad, flat-topped elevations. Unlike sharp, jagged peaks found in younger mountain ranges, plateau mountains have a more subdued and rounded appearance due to weathering and erosion over time. Examples include the Appalachian Mountains in the United States.