The correct answer is - Religion.
The Aztecs and the Mayans did had some similarity between them in their societies. Mostly, it can be seen in the religion. The Aztecs believed in and worshiped the Mayan god Quetzalcoatl, and their religious ways, including bringing sacrifices to the Gods, as well as building pyramids in the center of their cities as a sign of respect for the Gods. According to the Mayans, their God, Quetzalcoatl, left them, and went to the east, saying that he will return one day. the Aztecs believed in this, and it is how the confusion came to be when they first encountered Cortes, thinking that he is Quetzalcoatl.
