The <e1>pandemic</e1> was caused by the <e2>virus</e2> Yesinia pestis, better known as The Bubonic Black Plague, which infected the flees on the Black rodents.
The pandemic was caused
The pandemic was caused by the virus Yesinia pestis, better known as The Bubonic Black Plague, which infected the flees on the Black rodents.
<triplet> pandemic <subject> virus <object> Cause-Effect(e2,e1)