The mountain range that crosses the eastern part of the United States is the Appalachian Mountains. This range extends from Canada down to Alabama. Other ranges like the Cascades and Rockies are found in the western U.S. ;
The Appalachian Mountains are the mountain range that crosses the eastern part of the United States, extending from Canada to Alabama. They are one of the oldest mountain ranges in North America and are known for their diverse ecosystems and historical importance. Thus, the chosen answer is D. the Appalachian Mountains.
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