Answer:
The invention of new technologies like cramped planes, or busses, or even ships, has helped disease spread by providing it with a faster way to travel around on poeple and expand more.
They buy things, this putting money into the economy as a consumer.
A primary source would directly come from a witness and secondary source would be someone who got information through the grape vine. So in this case if it was directly made by her then it would be a primary source.
