Which three factors led to the rise of terrorism at the start of the 21st Century

The involvement of the Western Powers in political affairs of countries in the Middle East, as Western Powers tended to sponsor a particular candidate that had friendly views towards the West. The ongoing conflict between Israel and Palestine is a great issue in the Middle East region. Israel is an ally of the Western Powers. However, Israel's neighbors still strongly believe they have illegitimately settled in the territory where the country is currently located. The invasion of territories by the Western Powers' armies is a major cause for the retaliation of terrorist groups throughout Europe.