This definitely has to do with the excrement of animal feces. It's poop that does this, caused by farming.
When European settlers came over to the New World, they brought many diseases with them that the Native Americans had no immunity to. For this reason, they started dying from sicknesses and decrease their numbers by the millions.
Answer:
The Aftermath of World War II was the beginning of a new era, defined by the decline of all European colonial empires and simultaneous rise of two superpowers: the Soviet Union (USSR) and the United States (USA).