what purposes did the earthwork mounds of the adena and hopewell serve? how can archaeologists know that?

Archaeological evidence shows that approximately in the year 500 B.C. the Adena culture built cities and funerary mounds in the Midwest. For the year 100 B.C. Hopewell culture-related societies massively built mounds of land to bury their dead and other ceremonial purposes. Frequently these mounds had animal shapes and geometric figures that reflected aspects of their cosmogony. Some mounds reach 20 meters high.  

There are different protocols for archaeological research depending on the nature of the site or the objective sought.  Archaeologists can find out about this information after carrying out excavations in which they found the skeletal remains next to the objects that accompanied the bodies of dead people. They measured the depth of the findings and analyzed all material remains. To know the dates they used different techniques and dating methods such as “carbon 14”.

the correct answwer is d