Or...you can form a Hypothesis (2 minimum)

(An hypothesis is a statement (based on your best guess)

on what you think happened during the Black Death)

​​How did the Black Death start?... I think that since the plague originated in China, there must have been many rats in China. The bacteria that makes up the plague must have thrived under ideal conditions and evolved over time into the Black Death that eventually found its way to Europe.​



After you've done your research you might have to revise your hypothesis...

After investigating the cause of the Black Death I learned that the bacteria that causes the plague is called Yersinia pestis. This bacteria is closely related to its root ancestor Yersinia pseudotuberculosis. The high population of rats in China gave the new bacteria a way to freely transmit the disease from host to host (rat to rat) and then person to person.