Why do you think the europeans would want to import african slaves instead of using native americans to work on plantation

Hurr. how did lincoln respond to the events at fort sumter? a)he called for the mobilization of troops to put an end to the rebellion. b)he signed an ordinance to dissolve the confederacy. c)he called for the seizure of federal property throughout the south. d)he declared the end of slavery in the united states.