Give at least 2 reasons why the mound builders built their mounds

It was built by the Adena culture. The varying cultures collectively called Mound Builders were inhabitants of North America who, during a 5,000-year period, constructed various styles of earthen mounds for religious and ceremonial, burial, and elite residential purposes.

They mowt likely lived in caves or maybe rock houses,i know they are similar but its all i know