Atmospheric carbon dioxide comes from two primary sources—natural and human activities. Natural sources of carbon dioxide include most animals, which exhale carbon dioxide as a waste product. Human activities that lead to carbon dioxide emissions come primarily from energy production, including burning coal, oil, or natural gas.
1. Communism spreads in Europe2.Germany divided between East and West, 3.Berlin Wall Built, 4.Russian Revolution, 5.Fall of Soviet Union, 6. Germany Reunified