1. The assassination of Archduke Ferdinand an his wife by a Serbian revolutionary

2. Many fought in a network of trenches on one of the three fronts

3. Sample answer: a long ditch

4. Miserable

5. To help and protect each other in case of war

6. Allied Powers:Central Powers: Great Britain Germany France Austria-Hungary Russia Turkey Italy Bulgaria United States Japan

7. The Central Powers included Germany, Austria-Hungary, Turkey, and later Bulgaria

8. The Allies included Britain, France, Russia, Italy, and eventually, the United States and Japan

9. Each alliance wanted to keep the other from getting too strong

10. The assassination of archduke Francis Ferdinand sparked the first World War.

11. Europe

12. Germany

13. Russia

14. Weapons

15. Austria-Hungary

16. Serbia