World War I Crossword Puzzle

What was the British ocean liner that was sunk by a German U-boat
The strip of land in between the two trenches
The type of fighting used in WWI
France, Britain, and Russia form what?
Germany, Austria-Hungary, and Italy form what?
The man who shot and killed Archduke Franz Ferdinand
What letter did the germans try to send to Mexico?
The term most typically was used to refer to troops deployed to Europe
The bloodiest war in History
The canal that crosses central america
The system where destroyers escort merchant ships across the atlantic
Men register, and were randomly selected for service
Calls for international organization or league of nations
The treaty that ended WWI
Devotion of interest and and culture of one's nation
Germany must accept sole responsibility for the war
The acronym used to remember the four causes of WWI
Advertisements that spread ideas or rumors to help or harm a cause
German submarines
The name of Wilson's plan for world peace