Why did the fifteenth amendment fail to guarantee the vote to african american until the voting right act was passed to support it?

What made the settlement of oklahoma territory different from that of other territories

By choosing to resupply fort sumter, abraham lincoln risked a. abandonment of the fort by union soldiers. b. abandonment of the fort by confederate soldiers. c. the appearance of giving in to confederate secession. d. armed conflict with southern soldiers.

Which describes a significant different between the north and the south in the year leading up to the civil war