Why did early explorers not believe the mounds were made by ancient people?

Plz ! after the first battle of bull run general ivan mc dowell was removed from command of the union army he was replaced by a. general ulysses s. grant. b. general george mcclellan. c. general robert e lee. d. general george meade.

When the ottoman empire weakened, europe reacted by building a canal for trade with the ottoman region. ottoman nations achieve independence. cutting off most trade with the ottoman region. trying to take more control of ottoman lands.

Who were the copperheads? a. a native american tribe that rose up during the war b. northern democrats opposed to the war c. ships that ran the union blockade d. an elite force of union soldiers in the west