Conflict and Cooperation within the world is based on three main points: religion, economics, and similarities and differences between groups. With these three things, nations would make alliances or declare war, as people try to force the hands of the enemy for required resources that may satisfy the standard of living in the country, or to defend their homelands from intruders.
The 3 things you write about:
Paragraph 1: Difference of religion, and how it starts wars (you can name the crusades, for example)
Paragraph 2: Differences in economy, and the fall of the general world economy (you can give the example of Nazi Germany, WWII, and the Great Depression, for example)
Paragraph 3: Defense of homeland, and how it would start a war (you can name the War on terror, where the terrorists caused 9/11, and the US responded)
Summary: Summarize key points
hope this helps