Question

A result of the Louisiana Purchase was that

it increased the land available for American settlement.
it made the United States three times larger.
it increased the land available for European settlement.
it put the Northwest Passage under US control.

Answer 1

It increased the land available for American settlement (it only doubled the US's size so it's not that; by this time European influence in America was decreasing and they weren't creating new settlements in North America).