What are the core principles of International Relation

How does the field of International Relation study the world’s complexity? 2. What are the core principles of International Relation? 3. The levels of analysis and examples of each. 4. The different theories and how they explain the international system. 5. What are the differences between realists, liberals, marxists and constructivists? 6.How did the Westphalian system come about and how did it transform what came before it? 7. What challenges did state face, how did they did they overcome them, and are there new challenges emerging against the state today? 8. What are the different styles of foreign policy decision making? 9. How is foreign policy making impacted in a time of crisis? 10. Early US foreign policy. 11. What technological changes and political changes led to the stalemate of WWI? 12. How did the Versailles Treaty change Europe and the rest of the world? 13. What were the great challenges of the 20th century?