Final answer:
The interior lowlands of the United States are divided into the Great Plains, Interior Lowlands, and Interior Plateaus. Each subregion has different geological characteristics and formations shaped by glaciers and rivers.
Step-by-step explanation:
The interior lowlands of the United States are divided into three subregions: the Great Plains, Interior Lowlands, and the Interior Plateaus. The Great Plains are located to the west of the Interior Lowlands Province and consist of sediments that eroded from the Rocky Mountains. The Interior Lowlands Province covers the Midwestern states and is dominated by undeformed Paleozoic marine rocks that have been shaped by glaciers and rivers. The Interior Plateaus are located to the west of the Great Plains Province and are composed of sediments that are substantially younger and have a higher proportion of clastic material.