The Erie canal was opened on October 26 1825 by Governor Clinton. It had been first proposed in 1807 and constructed from 1817 to 1825.
The Erie canal made an immense contribution to the wealth and importance of New York city, which later became the chief U.S port and fostered a population surge in western New York.
It served to increase trade throughout the nation by opening eastern and overseas markets to mid-western farm products and it opened regions farther west to settlement. The Success of the Erie canal led to a proliferation of smaller canal routes in the region.
The best answer i see is C) The natural features in an area include mountains, deserts, and oceans because these were all aspects of keeping native people from wondering to far.
I would say we have better technology, so they can take part of the DNA and see when they were around. How long it's been since a dinosaur in the Triassic Era walked the earth.