An enormously influential biological exchange occurred when Europeans landed in the Americas, to the benefit and detriment of Europeans and Natives. Old World—New World plant and animal exchange resulted in sugar and bananas crossing the Atlantic while pigs, sheep, and cattle arrived in the Americas. The transfer of European diseases had catastrophic repercussions: influenza, typhus, measles, and smallpox devastated the Native American population. The Biological Exchange (also called the Columbian Exchange or Grand Exchange) is one of the most significant biogeological events of world history, affecting almost every society on earth and historians have only recently begun to question the event and the way it has been traditionally interpreted. In the traditional interpretation of the Biological Exchange, Indians lived in harmony with their environment in a pristine world and both the Natives and the environment were suddenly devastated following the arrival of Europeans. Biological exchanges of plants and animals enabled a better and longer life for Europeans, who took food items like potatoes and corn back to the old world were suddenly able to grow food to support their large population while reducing the population overgrowth by transporting humans to the new world.
Many European countries had what was referred to as a "Sphere of Influence" in China at this time. So, Secretary of State, John Hay, created an open door policy to allow all countries equal privileges in trade.
<span>The obligations of serfs were to work for lords and knights. Serfs lives were much more difficult than that of a lord or knight. Serfs didn't have freedoms like the lords and knights. Knights would sometimes serve the lord as well but could also be the lord of a castle. Serfs didn't have that option.</span>
