The answer to this question is Located <span>important routes for trade and travel
The lewis and clark expedition was also known as The corps of Discovery. This expedition was ordered shortly after united states bought Louisiana in order to explore the region. As it turned out, the expedition lead to several paths that could be used to travel natural resources, and the expedition contributed to the discoveries of most of United States western region today.</span>
Pretty sure it was new disease, since Columbus brought small pox, measles, and the influenza with him to America. Hope this helps!
Senator designate is selected by the president