How did the early West cause a cultural transformation in the United States? A: Mexicans and Americans were forced to live together after the Mexican War, resulting in a mix of cultures in the western United States B: Because of the gold rush, many cultures came to the West and interacted with each other, resulting in cultural awareness for the United States. C:The Transcontinental Railroad in the West allowed visits to foreign countries, and people were able to experience other cultures for the first time. D: The U.S. purchased the Oregon Territory from Britain and Mexico, and those citizens still lived there after the purchase, mixing their culture with American culture there.