The correct answer for the question that is being presented above is this one: "B. building of the transcontinental railroad --> disappearance of the frontier." The pair of events that did the first event most directly influence the second is the building of the transcontinental railroad --> disappearance of the frontier.
I believe an answer could be assimilation, as assimilation is the integration or process of people/ideas/culture into a bigger culture or society. It was one of the major results of immigration into the United States.
I hope this helps :)
Mondays and Thursdays is only 2 days a week. So 2.15x2 is 4.3 hours a week. 4.3x3= 12.9 hours every 3 weeks or 12 hours and 54 minutes
