The spreading of information twisted to the person's, group's, nation's advantage. These ads, movies, songs, etc that are shown to the public, are meant to change or support a point of view on something. In this case the Creel committee was created by presindent Woodrow Wilson to make propaganda encouraging Americans to support WW1.

90% of Americans opposed going into the war and with the help of propaganda the statistics turned into 90% of Americans supporting the entry of the war. They used songs such as "Over There"
(https://youtu.be/B6hRDS3LvQQ) to encourage civilians to enlist in the army and help fight the war "over there". The song describes how if they went "over there" that there parents and wife would be proud. This helped them complete there goal of getting soldiers to fight in the war. It also helped shield the seriousness of the war, one of their main goals.

The Zimmermann Telegram was a secret diplomatic message to Mexico sent by the Germans. In the message, there was a clear set of instructions for Mexico. The Mexicans were suppose to invade the United States, and annex ¨lost territory" within Texas, New Mexico and Arizona.  

 The message was suppose to be sent to Mexico, but was successfully decoded in by British cryptographers. The British held onto the message, until President Wilson received it on February 26. That was the same day Wilson proposed that the military starts to arm its ships against Germans. On March 1st, copies of the Telegram were published in newspapers. American opinion now swung towards the entrance of WWI. 

The United states had large investments and loans in the Allied countries. Loans to Great Britain and France soared to 2.25 Billion, and Germany stood at a $27 million dollar loan. President Wilson soon permitted loans to belligerents. 

The United States had large investments over seas in the Allied countries. With the war over sea, American investment was in danger. Large investments in Allied countries were put at risk.  If the Allies lost the war. All of the American investments would be lost. So, America decided to intervene and protect their investments.  

Unrestricted submarine warfare was first introduced in World War I. Germany declared the area around the British Isles a war zone. Meaning all merchant ships, including those from neutral countries, would be attacked by the German navy.
 Freedom of the seas is the right for ships to sail freely on the oceans without interference except in territorial zones.