Considering the passage above the completed one is this:
After the passage of the Homestead Act, settlers flooded to the Great Plains, where lumber was scarce. Barbed wire enables the settlers to fence in their lands.
As a result, the movement of Native Americans and cattle drivers was severely restricted, and the era of open range came to an end.
Well, if you look close enough there is proof look at the way that the continents are shaped and some fossils have been found in 2 places but on completely different continents.
