Why did the trails west often follow rivers for such a long distance?

Enlightenment philosophers believed that human civilizations are similar to nature in that they are a. violent and brutal b. wild and unmanageable c. governed by natural laws d. subject to divine power select the best answer from the choices provided a b c d

"the plan of removing the aboriginal people who yet remain within the settled portions of the united states . . approaches its consummation. . an extensive region . . has been assigned for their permanent residence. it has been divided into districts and allotted among them. many have already removed and others are preparing to go. . " removal of southern indians to indian territory, 1835 this passage is most closely related to a) imperialism. b) the civil war. c) westward expansion. d) the french indian war.

What change took place in the african slave trade in the 1500's?