Final answer:
The Mound Builders built the massive earthen structures for various purposes, including burial mounds for the elite and centers of worship. They also potentially served as places of worship for supernatural beings and had symbolic meanings. Farming, sporting events, and protection from hostile neighbors were not the main purposes of these structures.
Step-by-step explanation:
The Mound Builders, part of the Mississippian culture, built massive earthen structures for a variety of purposes. These structures served as burial mounds for the elite, who lived atop some of them. Some of the largest mounds were also centers of worship.
They provided connections to ancestors and were settings for religious rituals. The Mound Builders also used their structures as a way to mark time, act as compasses, document celestial events, and potentially serve as places of worship for supernatural beings.
While the exact reasons behind the construction of these structures continue to be debated, they were not primarily used for farming, sporting events, or protection from hostile neighbors.