“An unnatural alliance that was bound to fall apart after the defeat of the common enemy.” To what extent does this statement explain the origin of the Cold War?

From the May 2006 paper 2 DP history exam

 

  “An unnatural alliance that was bound to fall apart after the defeat of the common enemy.” To what extent does this statement explain the origin of the Cold War? 

From the markscheme:

This question offers a quotation for candidates to use as a structure for their answers on the origin of the Cold War. The “unnatural alliance” should be examined, both from the point of view of the previous enmity and divergent views and ideologies of the participants of the “unnatural alliance”, the communist USSR and the democratic free market exponents, USA, Britain and France and why they were drawn together to fight a common enemy: Hitler and Nazi Germany. The “falling apart”, between 1945 and 1948, should then be analysed and a judgment formed as to how far the split was caused by ideology and previous enmity, and how far by the disagreements, fear and mutual recriminations of the two sides in post war Europe, especially in both sides’ policies toward Germany and Eastern Europe. Finally a verdict should be given as to the “bound to fall apart” in the quotation.
 

Timed example under exam conditions from an excellent former student:

Another example of timed written essay: