How did submarines help world war you?

Submarines played a crucial role in World War I by disrupting enemy supply lines and conducting stealthy attacks on naval vessels. The use of unrestricted submarine warfare by Germany, particularly with U-boats, aimed to blockade Britain and cut off supplies, leading to significant losses for the Allies. This tactic prompted the United States to enter the war in 1917 after several American ships were sunk. Ultimately, submarines changed naval warfare dynamics, emphasizing the importance of underwater capabilities in modern conflicts.