One way to travel to the West was to sail around the tip of South America, the other way was to travel to the end of the railroad line and take a rough trail on land in wagons pulled by horses, mule, or oxen
All of this done with horses, oxen or mules pulling all of their earthly belongings and suppliesin a covered wagon. The Native Americans were also a threat. They were angry these new settlers were moving onto tribal lands. In the 1840's, the most famous trail that was used by the pioneers was the Oregon Trail.
Taking into account the statement above "Which was a feature of the relationship between the soviet union and the united states in the era leading up to détente?"
I believe it's because schools feel it is unnecessary and a very controversial topic. Besides that, schools inform students not persuade them to believe one thing or another.
