This kind of interaction is known as parasitism and the flea is the parasite. The parasites take advantage of the host and the host is never benefitted by the presence of the parasite.Parasites are normally smaller in size than their host and has the ability to reproduce very fast. The parasites do depend on their host, but they never kill their host. They live and depend on their host for an extended time of their life.Parasites do negatively affect the biological fitness of the host. The health condition of the host can deteriorate slowly.
The shortest lived known head of state is Jean I of France who ruled and lived for five days in 1316.
The last one. The south was known for farming so the last one doesn’t make sense
