It is believed that all of these people except the dispersed to their present location from the Nok area. PLease help me

Which would make the best heading for this list of notes about the migration of african-americans during the reconstruction era?

Plz where was the inca civilization located? a. in and around the andes mountains of south america. b. central america in southern mexico. c. the caribbean islands. d. the central valley of mexico.

One drawback of voluntary trade is that it a.requires two groups to use a common language b.can make one group dependent upon another for necessary goods c.doesn't occur unless there is a shortage of goods for at least one group d.forces groups to rely on themselves to produce all the goods they need