Name three postwar organizations that worked to improve conditions in the world

1. Treaty of Versailles
2. Hungary became an independent state under the terms of the Treaty of       Trianon;
3. The Ottoman Empire signed the Treaty of Sèvres on August 10, 1920, ending hostilities with the Allied Powers;
4. The new Republic of Turkey, established in its aftermath, signed a superseding Treaty of Lausanne in 1923, effectively partitioning the old Ottoman Empire.

Never hurts to have an extra. I hope these are right. They are the treaties made after WW1.  The Marshall Plan was made after WW2.