Answer: Because to the East the Missouri, and Ohio Rivers make up the continent's major river system. This system drains most of the interior planes of the United States. It also provides a an important network of waterways for trade and transportation. 7. Uranium. It is polluting the area with radioactive dust. 8. 60k to 800 mil total people. There were the Inuit. the Iroquois, the Cree, Cherokee, Choctaw, Plains Indians, the Navajo, the Pueblo nations , and the Mayans. 9 . They died off(most of them) The cause was wars diseases and being pushed off the land.
Explanation: sorry if that was long. an i have brainliest pls
