It spread through via international airline travel very quickly.
You didn't provide the answers, however, European Communist countries didn't have much choice since they were liberated by Communists during the war. The Asian countries did have a choice and chose to adopt it which is why there were many wars, both civil and one country fighting another like in Vietnam or Korea. They were supported by the Soviets and China.
Filth (like sewages)= how to keep it from potable water sources. Crime = too many poor people and not enough income available.
Disease = they were pretty dirty people, disease & death were at high rates.. many infected bodies to dispose of.
<span>C. to grind grain into powder that could be used for other purposes
Hope this helps!</span>
