One thing that makes piecing together the history of sub-saharan africa easier for researchers for oral histories. oral history is

Oral history is the transmission of historical knowledge orally over time. This means that the traditions, past, and historical events of groups of peoples are not written down in text or books but instead are transmitted through oral histories over time. Oral histories are common in cultures and societies all around the world including Sub-Saharan Africa. 

Explanation:

your answer is: a passage or quotation taken or selected from a religious book example: the bible, torah, and the quran.

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