Why did hiram revels and other reconstruction era office holders try to reassure whites?

During the Reconstruction period of 1865–1877, federal law provided civil, White Democrats had regained political power in every Southern state. African Americans and former slaves became Republicans and officeholders. Hiram Rhodes Revels was the first African American to serve in Congress as a senator.

switch around #3 and #4

explanation:

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(d) rivers.

explanation:

civilizations developed around rivers because their waters provided places to hunt and fish. also, as the rivers flooded, the lands around them became fertile. this allowed them to support farming. this is especially true of the nile river, which flooded the same time each year.