How were U Boats used in WW1 (brainliest if you can write it in your own words)

Germany retaliated by using its warships to sink the neutral ships provided by the Allies. The fearsome U-boats prowled through the Atlantic, armed with torpedoes. They became Germany's only weapon of gain as Britain essentially blocked the flow of German ports.

Explanation:

U-boats were military submarines used by the Germans. While they were useful against warships, U-boats were the most effective in economic warfare by blockading coasts so resources could not be shipped to Germany's allies. WWI was the first major war that employed submarines in warfare.