Question

In Medieval Europe, it took a few years for the Black Death to consume all of Europe. In 2009, the H1N1 disease spread all over the world in a few months. Considering the information on the map, how might the H1N1 virus have spread so quickly throughout the world?
The virus was spread throughout the world by flocks of migratory birds.
The virus was spread throughout the world via international airline travel.
The virus was spread throughout the world via contaminated meat.
The virus was spread throughout the world by infected street rats.

Answer 1

The virus was spread throughout the world by flocks of migratory birds.
This would be that the flocks of birds caught the disease and then migrated and spreded it to that population

The virus was spread throughout the world via international airline travel
This would be that it is in the air vents and the filters

The virus was spread throughout the world via contaminated meat. 
Because the whole world trades with each other and if one country is infected then that could potentially kill the whole world

The virus was spread throughout the world by infected street rats.
This would be the exact same as the black plague

Hope this helps :D

Answer 2

The answer is via international airline travel: B