To accurately answer the question about the regions where the Mound Builders primarily lived, it's important to refer to the geographical details provided in the passage. The Mound Builders lived from the Great Lakes to the Gulf of Mexico, and east of the Mississippi River to the Appalachian Mountains.
Based on this description, the two regions that best fit this description would be:
- Region A (assuming it is in the northern part near the Great Lakes)
- Region D (assuming it is in the eastern part towards the Appalachian Mountains)
Please confirm which regions correspond to these descriptions on your map for a precise answer.