How might a flashback add complexity and interest to a story? - By revealing important events in a characters' past.
- By showing that the main character is keeping secrets.
- By hinting at important plot developments to come.
- By relieving the boredom the regular narrative.

Please make sure your answer is correct this is for an exam!!

By revealing important events in a characters' past.

Explanation: Flashbacks are moments in which the author goes back to the character's past and they help explain the reasons or the motivation a character has to do certain thing. The answer could also be the third one, but you can also accomplish the third one without using flashbacks, so, the correct  answer is the first one.  

I think the correct answer is true. Bias and interpretation can influence my perspective as an observer. These things when known will give you an idea about the results and it you will be expecting this to happen. Your mind will not be open to other results that you might see.