Phrasal verbs account to form a particular part of something: Teenagers account for the vast majority of our customers.
explain the cause of something: How do you account for the sudden disappearance of the files?
to be the cause of something: HIV accounted for over 20,000 deaths within two years.
to know the location of something: We have accounted for every item that was missing.
have record of how money has been spent: Your job as a treasurer is to account for every penny that is earned or spent.
to think about something before: The authorities failed to account for the fact that the population is growing.