Answer:
The main cause for 9-11 terrorist attacks was:
Al-Qaeda's goal of punish the United States for supporting Israel
Explanation:
The attacks motives of Al-Qaeda were explained in Bin Laden (leader of Al-Qaeda) announcements of 2002 in the text "Letter to America" in which Bin Laden stated:
"The expansion of Israel is one of the greatest crimes, and you are the leaders of its criminals. "