Both biographies and autobiographies cover the important events in the subject’s life.
Explanation:
Both biographies and autobiographies relate the most important events in the life of the subject under consideration. The difference between the two is very simple. An autobiography is the narration of one´s own life´s events, their relevance and their significance. A biography, on the other hand, is an account of the events of a person´s life told by a second party, it can be a first-hand account, that is to say, told by a person that actually knew or was involved with the subject of the narration, or it can be based on historical documents or other forms of records.
