Answer: The Incas unified their empire through the spread of their language, compulsory military service for conquered peoples, and via a vast and sophisticated network of roads.
Explanation: The Incas unified their empire through the spread of their language, compulsory military service for conquered peoples, and via a vast and sophisticated network of roads. The Incas made sure to spread their Quechua language throughout the empire for unity.
(Ignore the explanation if you want because it’s long, this information is from a reliable source.)