All the following countries participate in nafta except united states mexico greenland canada

The correct answer would be the following: All the following countries participate in NAFTA except Greenland. The NAFTA (North American Free Trade Agreement) is an international agreement signed by Canada, Mexico and the United States on January 1st, 1994. It created a trilateral trade bloc of all three north american countries. Its main objective is to eliminate trade barriers between the three nations, so that they could exchange goods and service between themselves at a more competitive cost.

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d. because dr. laguardia selected a widely used measure, his study generalizes to has strong external validity. external validity has limited external validity. other applications of this measure.

the widely used measure that he applied to his experiment was the benton facial recognition test. it employed on to football players and as result, only players who suffered brain concussions did not pas this test. and although it has an external validity, it is limited because it isn't general to apply to other population.