After the United States purchased the Louisiana Territory, America’s western boundary shifted to the , which is a(n) boundary.

Rocky Mountains; physical

Explanation:

United States and France came into the agreement of the land which is popularly termed as The Louisiana Purchase. It was the United States that acquired the large part of the land situated in the west of the Mississippi River. The territory of Louisiana covered the area as  Mississippi river in the east to the Rocky mountains in the west. It stretched from the Gulf of Mexico in the south the Canadian border in the north.

no statements but ok.

the statement that best describes the idea of manifest destiny that was used in the 19th century would be that "it was fate that the united states would continue to  expand westward," since people thought the us was "destined" to do so.