The protagonists were the Allies (centred around United Kingdom, France and the Russian Empire - and joined later by Belgium, Serbia, Italy, Japan, Greece, Romania, Portugal and the United States) and the Central Powers (German Empire, the Austro-Hungarian Empire, the Ottoman Empire and the Kingdom of Bulgaria).
Germany was Britain's main enemy.
During WW 1, submarines played a major part of a major war for the first time. The role of a submarine was basically to use torpedoes to sink enemy warships and cargo vessels.
War is a major combat operation that seeks to defeat or destroy enemy armed forces. Some examples include World War I and World War II.
The code that was never broken by the enemy was based on the language of Navajo. Neither the Japanese, nor the German could break the code words. The code was used by people that fought in the Pacific war during world war 2.
major. A+
I would say Germany. Although Japan was a big enemy.
Germany.
Japan
Germany was Britain's main enemy.
They were not placed anywhere. Japan was not an enemy in World War I.
The question is unanswerable as asked since it does not define who the "enemy" is.
Germany and Japan
During WW 1, submarines played a major part of a major war for the first time. The role of a submarine was basically to use torpedoes to sink enemy warships and cargo vessels.
Japan
Russia.
Japan & Germany .
Their language was indecipherable to the enemy