If the exchange rate between U.S. dollars and euros changed from 0.90 euros per dollar to 0.78 euros per dollar, what might have caused this change? an increase in European tariffs on goods made in the United States. a decrease in European tariffs on goods made in the United States a rise in the interest rate differential because American companies benefited from higher returns a new fertilizer being invented that only works in U.S. soil and that makes growing all crops much cheaper