Re: Answers
Cause of war:
I suspect that there are many reasons that people will start a fight with each other.
Some reasons may be misunderstandings, disagreements, fear, greed, hate, irrational mental behaviour, etc..
On the internet I found these sites that touch on the subject.
Religion against the same religion.
http://news.ca.msn.com/top-stories/israeli-girls-plight-highlights-jewish-extremism
Explanation of the cause of War.
http://emotionalliteracyeducation.com/war-cause-solution.shtml