Final answer:
Geographical barriers prevented direct contact between the Aztec civilization and Inca Empire, making trade between them difficult.
Step-by-step explanation:
Geographical barriers prevented direct contact between the Aztec civilization and Inca Empire, which is one reason why they were unable to trade with each other. The Aztecs were located in Mesoamerica, while the Incas were in the Andes region of South America. The vast distance and diverse geographical features, such as mountains and deserts, made it difficult for trade routes to be established between the two civilizations.