The US intelligence beforehand had deciphered messages laying out the Japanese plan.
In the story of Oedipus he was given a prophecy saying that he would kill his father and marry his mother. And in the end of the story he does end up killing his father and marrying his mother. This is foreshadowing, a clue or event that has happened before that tells of an event that will happen in the future.
The answer is imperialism and colonization. Leading up to WWI, Europe was in a heated war over colonizing the Middle East, South America, and Africa. Conflicts over land and resources led to much of the driving factors of WWI.
I hope that helps! :)
