The Oregon trail was the most used trail during 1843 to 1870 and ran from Independence, Missouri, to the Willamette River valley. It was made from 1811 to 1840. There's an old-timey game about it too! Hope this helped!
Constantinople was able to fight back against the numerous
invasion attempts before 1453, but with each fight it got weakened. This
resulted in the fall of Constantinople in the year 1453, at the hands of
Ottoman Turks. Constantinople was not only fighting against the Turks, but also
against the fellow Christians. The Turks did not care about the Muslim population
living in Constantinople. Constantinople never grew stronger with the
resistance they put up against the several external aggressors. If that has
been the case, then they would not have been defeated by the Ottoman Turks.
Since Slaves we're crammed into ships, they often died of disease, as diseases spread much more effectively when people are constantly in contact with each other, as they often were because so many slaves were fit onto each ship. Think about it: You're more likely to catch a cold if you get coughed on no matter what you do , because you are always close to the sick person.
C. Civil War because world war 1 & 2 were in the 20th century
B. Achieving great power should be the correct answer.