What problems threatened the peace after world war i?

 For one, the Versailles Treaty was perceived by many to be a bit too harsh when it came to Germany. Hitler was able to exploit this for propaganda purposes. (Though had it not been for the Great Depression, the Nazis would've never been able to gain power) Also, the United States not participating in the League of Nations (forerunner to the United Nations) was another problem.

Master planned communities outside of chicago. note: population density means people living in an area per square mile. chicago, an urban and highly populated area has a much more higher density than a desert, amish community, settlement, or nomadic region.

Ibelieve it would be d. philosophy.hope it !