In the 1340s, the black death spread to europe as a result of

In the 1340's the Black Death spread to Europe primarily from Asia through merchants who came to visit Italy. The disease itself originally came from parts of Asia and it took many years before it spread to Europe. Once in Europe it spread very rapidly, due to bad hygiene and close living quarters. Also the cities were not very clean and people often threw garbage on the streets, thus making it easier for the disease to spread.

 The Black Death (bubonic plague) spread to Europe as a result of merchant ship contacts between Europe and regions to the east where the disease had originated.

Context/details:

The History Channel gives this report of the coming of the Black Death to Europe from the Central Asia region:  

The disease spread to Europe and killed more than a third of the continent's population.   Fleas on rats that were on board the ships are usually blamed for the spread of the plague -- though new research suggests the transmission of disease-infected lice from person to person was more likely the main cause of the pandemic.

A recent paper published in the Proceedings of the National Academy of Science has cast much doubt on the idea that rats were the primary cause of the Black Death's spread. A team of researchers from the universities of Oslo and Ferrara have concluded that the spread of the disease mostly occurred due to lice and fleas on human hosts (not rats). Prof. Nils Stenseth, from the University of Oslo said: “The conclusion was very clear. The lice model fits best. ... It would be unlikely to spread as fast as it did if it was transmitted by rats.  It would have to go through this extra loop of the rats, rather than being spread from person to person.” (Quoted in January 16, 2018 article in The Independent.)

Ultimately, the spread of the plague occurred the way communicable diseases typically spread.  With any communicable disease, which is spread by communicating (moving) from one person to another, as long as there was some form of contact then the disease could spread.

the map that was shown mostly had eastern asia highlighted. the answer would mostly likely be "the spread of communism into eastern asia set the stage for the korean war."

hopefully this .