Navigable water offered easier access to trade and employment
The correct answer is the U.S. troops - on behalf of the U.S. government. The period between 1820 and 1860 saw the decline of the conditions of the Indians in American territory. Many were decimated, thousands of them were forced to leave their homes in the South and move west of the Mississippi Rivers (this is the so-called Trail of Tears), and many others were even slaved.
Decreased because more products were made quickly by machines.
Product manufacturing became cheaper during the rise of industrialization, because machines allowed for a more efficient production (more products were made at a faster speed). In addition, there was a increase in the supply of workers that had moved to industrial areas to manufacture such products.
