USA HISTORY

Detailed explanation-1: -Answer and Explanation: The Appalachian Mountains slowed English settlement from moving west. The Appalachian Mountains served as a natural barrier to prevent early English colonists from moving into the western territories. The French claimed the western region of the Untied States in the early to mid-18th century.

Detailed explanation-2: -Weathering and erosion prevailed, and the mountains began to wear away. By the end of the Mesozoic Era, the Appalachian Mountains had been eroded to an almost flat plain. It was not until the region was uplifted during the Cenozoic Era that the distinctive topography of the present formed.

Detailed explanation-3: -The crust that is now the Appalachians began folding over 300 million years ago, when the North American and African continental plates collided. Plate tectonics created this ancient mountain range, then called the Central Pangean Mountains . . . and plate tectonics tore it apart.

Detailed explanation-4: -The ocean con tinued to shrink until, about 270 million years ago, the continents that were ances tral to North America and Africa collided. Huge masses of rocks were pushed west-ward along the margin of North America and piled up to form the mountains that we now know as the Appalachians.