Final answer:
The presence of an I-shaped Mesoamerican-style ball court and the production of colorful macaw feathers, which indicate cultural exchanges and trade networks, serve as strong evidence of the influence of Mesoamerican civilizations on the builders of Casas Grandes.
Step-by-step explanation:
Strong evidence that the builders of Casas Grandes were culturally influenced by Mesoamerican civilizations farther south includes the architectural similarities that align with what is known about pre-Columbian Mesoamerican cultures. The presence of a large I-shaped Mesoamerican-style ball court is particularly indicative of the connection, as it is a feature widely associated with those cultures and not typical of the Anasazi architecture. Furthermore, the production of colorful macaw feathers at Casas Grandes used in Anasazi rituals indicates the existence of trade networks and cultural exchanges between the regions. Thus, despite resembling the Anasazi communities superficially with its adobe design, Casas Grandes embodies distinct Mesoamerican cultural influences, such as the ball court and trade in luxury goods.