Scholars of Africa have had to be creative and resourceful in reconstructing early African history, particularly history prior to the first written accounts, which began to be recorded by Arab travelers around the eighth century. Historian Jan Vansina coined the term upstreaming to describe the method by which Africanist historians reconstruct very early African history. Which of the following best describes this process? Historians of Africa base the core of their findings on African oral traditions, which detail the ways in which African societies have changed over the centuries from the ancient past (upstream) to modern day (downstream). Historians of Africa rely heavily on geography to determine the spread of languages, social customs, and trade due to the well- documented theory that these things are carried from one society to the next along waterways, from locations upstream to locations downstream. Historians of Africa must both consider historical accounts and examine aspects of later African social