Where did chiefdoms, cities, and kingdoms arise in Sub-Saharan Africa and why? On which forms of agriculture, urbanization, and trade were they based?"
a. Chiefdoms arose in coastal areas due to maritime trade.
b. Cities emerged along river valleys because of agricultural fertility.
c. Kingdoms developed in deserts due to nomadic trade routes.
d. Chiefdoms, cities, and kingdoms were based on a mix of agriculture, urbanization, and trade.