And B. physical systems because there are volcanoes, oceans, land, mountains, forests
The World War II was a reminder for many blacks of the inequality of American society, and a black soldier said, "Just carve on my tombstone, "Here Lies a black man, killed fighting a yellow man for the protection of a white man." There were changes to America's economy as well during and after the war, and in particular, the war time boom. The biggest contributor to the victory in the WWII was industry, and industries that had been inactive were now "humming with activity". Many factories were converted make war vehicles; such as tanks and flamers, and the Willow Run Factory was able to produce one B-24 bomber every hour. The prosperity went all through America's society, and government spending rose dramatically from $9billion in 1940 to $98billion in 1944. Wages increased hugely all over the country from rich to poor. Also, big businesses, especially those involved in the defence industry, became much more powerful, and surprisingly, military spending remained between 8 and 20 percent of GNP in the 40 years after 1945.
Paper from the Tang/Song dynasty to the Islamic empire, also because of that the Islamic empire has adapted paper money that is originated from China
