Answer:
When it comes to 18 all I can say is that the cities are near the border in the warmer, more fertile areas of the country. A lot of the area is still cold, plus the closeness to the USA adds an economic advantage. So for #18, it's because of the fertile growing land and proximity to its closest trading partner. For #19, I'd say they're close to the ocean for one. Mexico trades oil on a global scale, so the richest places are on the ocean/seas. This differs from Canada who trades a lot with the USA, so their trade lcoations are close to the USA. Meanwhile Mexico uses considerably more sea trade, therefore their better cities are closer to the ocean/seas.
Explanation:
AP Human Geography and a bit of logic. it's a rough answer and I'm not sure it's right but I feel like it answers the questions.
Mountains may prevent moisture-laden winds from reaching dry areas, as the Sierra Nevadas do to Nevada.
Hope this helps
Belgium,Denmark, Poland, Austria, France, Norway, The Netherlands, Czechoslovakia
The answer is going to be c.
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