Which of these best explains why most of canada's population has settled near its border with the united states? a) canada is populated primarily by former american citizens. b) canadians prefer the culture of the united states to that of their own. c) the climate there is less harsh than in more northern areas of the country. d) there are few resources north of the united states to sustain large populations.

C 

The answer is C that the climate near the border with the US is more temperate than further north so consequently most Canadians want to live where it is less harsh. At both oceans ie the Pacific and Atlantic they moderate the climate somewhat especially on the Pacific coast. But at the same time, Canadians are hardy and there are a few cities further north like Edmonton and smaller cities like Yellowknife in the Northwest Territories. 

The answer to the question is c.

81 is a composite number