How How were American borders expanded and what were the political social and economic reasons for doing so ​

During the early 1800's, settlers moved westward over the Appalachian Mountains into the new states and territories. Many of these pioneers even settled beyond the country's western boundary. They flocked into Texas, California, and other western lands belonging to Mexico.

answer; for children with two myopic parents,the likelihood of becoming myopic is ) correlated with the number of hours spent playing sports each week;