What is a main characteristic of the Appalachian Mountains?

The Appalachian Mountains are primarily known for containing large deposits of coal, which has played a significant role in the development of the region's economy and industry. The mountain range, stretching from Canada down to Alabama, is rich in natural resources, and coal mining was one of the most important industries in the Appalachian region, especially during the 19th and early 20th centuries. The presence of coal deposits is attributable to the geological history of the area, which includes the formation of sedimentary rock layers that are rich in organic material.

Other options are less accurate in describing the characteristics of the Appalachian Mountains. For example, they are not the tallest mountains in North America; that title belongs to the Rocky Mountains. Similarly, the Appalachian Mountains do not run horizontally across the continent; they run in a northeast-southwest direction. Lastly, the mountains are primarily located in the eastern United States, not on the west coast, which is home to different mountain ranges like the Sierra Nevada. Thus, the richness of coal deposits is a defining characteristic that sets the Appalachian Mountains apart.