Why did american exports to germany severely decrease during the war

Because of the threat of merchant ships being sunk by U-boats, but also because the US didn't want to support the possible enemy (depending on what war you are talking about). The US also became very anti-German, even re-naming the hamburger and other foods.

Germany lost to the allies in WW1 and suffered huge territorial losses giving away its land and population to Poland, Russia, France, Belgium an Denmark and ultimately had to sign The Treaty of Versailles.

i do not know if this question has options, but a main impact of the federal reserve act of 1913, which created the federal reserve bank, was the international use of the u.s. dollar, which soon became the world's leading currency - particularly during world war i, since many nations around the world asked the united states for money.

d.prevent the spread of communism outside of eastern europe.