It is important to remember that this is only a 6 mark question, and so it cannot take up too much time in the exam. However, to get the top mark you must explain two reasons and so it is vital you do this quickly. Firstly, the Treaty of Versailles did not allow for some of Wilson’s 14 points to be realized. Wilson wanted freedom of the seas and Britain disliked this, being the dominant naval power at the time. Moreover, the self determination that Wilson sought for every country was not realized in Germany as large areas of German land was given to Poland despite having German inhabitants. Once you have made your two points and explained them, there is no need to write anymore.