What a explanation contains and what can be used in a explanation

LI. What is an explanation
For writing we had to write about what an explanation contains and what could be in a explanation.
A explanation contains a piece of information to write about. For a example: how does a I pad work. You have to give every detail on how a I pad works and why it works. Things that can be used in an explanation could be Past third, Tense person, Passive times and Time connectives.