Final answer:
The Dyula or Djula specialized West African groups dominated trade networks in medieval empires and kingdoms in West Africa, which were known for trading valuable commodities such as gold, salt, ivory, textiles, and precious stones.
Step-by-step explanation:
The Dyula or Djula were specialized West African groups that dominated trade networks. Trade in commodities such as gold, salt, ivory, enslaved people, textiles, and precious stones played a vital role in the economy and cultural practices of medieval empires and kingdoms in West Africa. These empires, such as Ghana and Mali, connected West Africa to other regions like the Mediterranean, Europe, and the Near East through their control of trade routes and valuable commodities.