The Magyars, the Vikings, and Muslims
The significance was that these allowed goods to be transported much faster than by horse. Canals allowed for things to be imported and exported much more easily.
The complaint is called a case, and the one against the complaint is called the defendant
The answer to your question will be 3
The reason we joined in world war one was due to the germans sinking merchant ships that had US citizens on them and they were also sinking some of our own ships. Due to that President Wilson involved us in the war.