Final answer:
The Southeastern Indian Culture of Texas, characterized by agricultural practices and mound-building, had an economy most similar to the Anasazi Culture of the American Southwest, which also relied on agriculture and created significant architectural structures.
Step-by-step explanation:
The Southeastern Indian Culture of Texas would be economically most similar to the Anasazi culture of the American Southwest. Both cultures were agriculturalists that relied heavily on the cultivation of key crops. The Mississippians, part of the Southeastern Indian Culture, practiced large-scale agriculture mainly based on corn, as did the Anasazi, who also relied on corn as a staple of their diet, along with other crops such as beans and squash.
These agricultural practices allowed both cultures to support dense populations and develop complex societies with specialized artisans. In addition, the Anasazi and the Mississippians produced significant architectural earthworks, such as the Anasazi's multi-storied structures and the Mississippians' mounds, which served a variety of ceremonial and practical purposes.