What does Flashback effect on a traditional plot structure

Flashback means: 1. A scene in a movie, novel, etc., set in a time earlier than the main story. 2. A sudden and disturbing vivid memory of an event in the past, typically as the result of psychological trauma or taking LSD. Have you read a book, when the main character recalls his memory. When he remembers his past and bring that scene, thats a flashback. Now, your question is asking you is define flashback and explain it in a complete sentence on how it effects plot structure, how does it effect you when reading flashbacks. A flashback is a tool used in writing to allow a character to explore events occuring at a different time. The reader follows the characters thoughts as they examine and earlier situation. This can be essential to the story in that, it can give needed background information. However, sometimes a flashback can upset the rhythm of the story and, therefore, have a negative effect. This is rare, most often a flashback serves a needed purpose by more fully examining a person or situation.

It make sure what's happening next to the story