Why were the Woodland Indians known as Moundbuilders?

Because they buried their dead in large mounds

Explanation:

Mound Builders were prehistoric American Indians, named for their practice of burying their dead in large mounds. Beginning about three thousand years ago, they built extensive earthworks from the Great Lakes down through the Mississippi River Valley and into the Gulf of Mexico region.

a, c, & d are correct:

they wanted lands to settle the extra population.

they wanted new markets for english goods.

they wanted to avoid civil war.

photos creat an ovveral image of the civil war