In what ways were the world wars a motor for change in the history of the twentieth century?

1. The destructive national hostile between European states that had led to wars were dissipated following the second world war
2. The world wars led to the collapse of the European colonial empires
3.brought the united states to the center stage as a global power
4.the needs of total war led to the expansion of government authority
5.the destruction brought by the wars led to a widespread disillusionment among European intellectuals with their own civilization
6.the political map of the world was radically altered
7.communism emerged as an important political movement