Why was slave trade practice in East Africa

Africa?

In central East Africa, ethnic groups such as the Yao, Makua and Marava were fighting against each other and entire peoples within the continent traded with people they had captured through wars. "Thus Arab Muslims encountered already existing structures, which facilitated the purchase of slaves for their purposes..

yellow fever and other tropical diseases

because its important to learn about other countries and how high tech they are compared to us. also its good to learn about other cultures and how ours differs and in common also we need to learn about companies that we still buy since they ship it here.