The migrated to East Africa and displaced other tribes.

If you are talking about european countries coming to east africa and separating people into different tribes then yes that statement is correct. The europeans came to east africa and devided countries like congo, Burundi, Uganda and Tanzania up into different countries and to make things worse they separated the people into different tribes which even started a genocide in Rwanda

Explanation:

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.