Final answer:
Illinois preserves the Cahokia Mounds through legal protections, funding for research, public education via the Cahokia Mounds Museum Society, and by managing the site as a State Historic Site to ensure its continued conservation.
Step-by-step explanation:
The state of Illinois has played a significant role in the preservation of the Cahokia Mounds site, which is an important historical and archaeological landmark. As the site of a pre-Columbian indigenous city near present-day St. Louis, it was once a hub of political, religious, and trading activities. Given the historical significance of the mounds, Illinois has taken responsibility mainly through legislative protection measures, funding for archaeological research, and the development of the Cahokia Mounds Museum Society, which works to educate the public and preserve the site. Additionally, the region's designation as a State Historic Site and its management by the Illinois Department of Natural Resources ensure systematic conservation efforts. The Cahokia Mounds site is a testament to the sophistication of indigenous cultures, marking it an invaluable part of both Illinois' and North America's heritage.