American culture and American society has been greatly impacted by human migration. The Oregon Trail and Transcontinental Railroad made distant land available for settlement and increased trade from the United States. It also had the effect of A. keeping American culture and influence from spreading west of the Mississippi. B. destroying the Great Plains by making the land unsuitable for ranching. C. separating Spanish holdings in Mexico from Spanish holdings in western Canada. D. spreading American and European culture further west to the Pacific Ocean.ont, a Yankee is someone who eats apple pie for breakfast. Considering the anecdote above, which of the following statements about social identity is true? A. There are no boundaries when defining the identity of a person or group. B. It forms when people agree on what distinguishes themselves from others. C. Social identity is static, and once it's defined it cannot be changed. D. Social identity means the same thing to all people, regardless of location.