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.

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).

begins a massive airlift of food, water, and medicine to the citizens of the besieged city

polling is a process and the outcome is not involved in the process itself.

the outcome, which is an unfavorable rating for a particular candidate is not affected by the mechanical process of polling.

it rather depends on the number of people voting in favor of the candidate.

this is an outcome of people's preferences.