<span>Their progress and wealth is highly dependent on the harvests, and
the price of grain. They probably have to import some industrial
products and if they had a bad year (weather, other catastrophies, poor
technology) they can't get the necessary amount of industrial products
in exchange for their surplus e. g. in grain. </span>
The correct answer is - biomass from the decomposing grasses.
The Midwest is a region known for its highly fertile soil. The reason for this is that the weathered bedrock combines with huge amounts of biomass. The biomass is almost entirely form the grasses. The grasses grow naturally in this region and they dominate the landscape. They grow and die out relatively quickly, as most of those grasses are one season grasses. They manage to create very large amounts of biomass every year, and also they decompose very quickly. The grasses also are high in nutrients, so once decomposed, they give the soil a lot of nutrients as well, which makes it very fertile and suitable for agriculture.
I think the correct answer is true. <span>The establishment of the European Union has created more boundaries within Europe then in the past. The European union had made some conflicts in the continent since some were not in favor with it. Hope this answers the question.</span>
The correct answer is C: the Mackenzie River!