Answer:
Event: the fall of the Western Roman Empire.
Question: Why did the Western Roman Empire fall?
Paragraph:
The Western Roman Empire fell in 476, when germanic chief Odoacer deposed the last Roman Emperor: Romulus Augustulus, who had been emperor for less than a year. This event ended five centuries of Roman rule in Western Europe, and is often established as the moment that ended Classical Antiquity, and started the MIddle Ages.
Sources: there are many sources available that dig deeper into this topic, from primary sources to secondary sources. Primary sources however, are often biased, and written in Ancient languages like Latin and Ancient Greek, and as a result, are mostly left to specialized historians. For this reason, a secondary source would be more appropriate for a student.