Will mark brainlist!

After world war 1 immigration was based on

Prior to the presence of europeans on the continent, the slave trade in africa a) did not exist in any form. b) was limited to internal trade only. c) included the trans-saharan and indian ocean slave trade. d) was rarely needed due to the lack of an agricultural economy.

Was the civil war inevitable? could anything have been done through compromise to stop it, or did it have to happen?