Answer:
Explanation:
The Rockies impacted the ability of settlers to travel to the West coast of the United States. The difficult traverse of high, snowy peaks and the short period of safe travel allowed by weather each year presented massive challenges to migrating pioneers.
How did it cause it?
During the Paleozoic era, inland seas covered much of present-day North, depositing thick layers of marine sediments that would later turn into sandstone and limestone. At about 285 million years ago, a mountain building processes raised the ancient Rocky Mountains.