Well this depends on the year and the quarter but lets take the data from the 2017. In 2017, in the third quarter of the same year, US imported 10 million petroleum per day (most of it is crude oil). Out of that 10 million barrels per day 7.5% come from Saudi Arabia according to the US Energy Information Administration.
Changes in the earth's climate caused ice sheets to grow and cover most of Canada and some of the northern US almost 15 000 years ago. This is known as the last Ice Age. For the last two million years, the earth has shifted between ice ages and warmer periods. Ice ages are caused by slight changes in the way the earth orbits around the sun. Huge continental glaciers or sheets of ice moved down from the Artic and covered Canada, North America and much of Europe.
Answer: "cognitive" .
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The answer is: "cognitive psychology" .
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