How did unrestricted submarine warfare lead to the u. s involvement in ww1?

Unrestricted submarine warfare was first introduced in World War I in early 1915, when Germany declared the area around the British Isles a war zone, in which all merchant ships, including those from neutral countries, would be attacked by the German navy. German ships would attack no matter who they were

Athena (goddess of wisdom) gave perseus an unlikely tool to defeat medusa that requires brain over brawn that was instrumental in his victory against medusa