Final answer:
The theme of human-environment interaction is best illustrated by people building dams and levees along the Mississippi River to control water flow and prevent flooding.
Step-by-step explanation:
The best illustration of the theme of human-environment interaction is option A: People build dams and levees along the Mississippi River. This demonstrates how humans modify the environment to control water flow and prevent flooding. Dams and levees help protect nearby communities and manage water resources.
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