U-boats aka submarines
Because the British blockade prevented the United States from trading with Germany.
The British blockade hindered trade between Germany and the United States in 1915.
Britain set up the blockade.
A British blockade
A British blockade
The British blockade tried to starve the Germans and their allies into submission during World War I. It also allowed the British forces to have dominance over the seas and attack at will.
It increased America's economic ties with the Allies because British blockade of Germany caused American trade with the Central Powers to virtually cease.
superman
use of submarines
submarine
The Germans used a AT-4
Germany blockaded Britain in ww1 because her people were starving and suffering. Germany did this after Britain had already blockaded Germany to try and win the war.