Here are the answers to your questions:
Question 1:
Romans and Arabs
Question 2:
South Africa
Question 3:
1950s
Question 4:
Rwanda and Burundi
Question 5:
There was exportation of slaves during the slave-trade era.
Question 6:
Institutionalized separation between the white regime and African tribes.
Question 7:
Ethiopia and Liberia
Question 8:
South Africa / ending apartheid.
Question 9:
initiate attacks of rival tribes in order to profit by selling captured Africans to the Europeans.
Question 10:
establish peaceful diplomatic relationships amongst all African countries.
Feel free to reach out if you need further assistance!