Which statement about ancient American civilizations expresses a historical theory rather than a historical fact? A. The Incas lacked a written language. B. The spread of disease caused the downfall of the Mayan empire. C. Human sacrifice was an element of the Aztec religion.
The spread of disease caused the downfall of the Mayan empire (B.) is not a historical fact, but is rather a theory developed by historians as research has been conducted of ancient American civilizations.