Final answer:
The Octagon Earthwork in Newark, Ohio is currently an archaeological site, reflecting the Hopewell culture's astronomical knowledge and its heritage significance.
Step-by-step explanation:
The current use of the Octagon Earthwork in Newark, Ohio, is as a c. Archaeological site. This site is part of the Hopewell culture earthworks and remains an important cultural and historical area reflecting the advanced astronomical knowledge and societal organization of its builders. The Octagon Earthwork was primarily used by the Hopewell culture to align with the movement of the moon and to predict lunar eclipses and other significant seasonal events. Today, it allows archaeologists and historians to study the technological and social sophistication of the Native American societies that constructed it.