Understanding what is being asked is very important for a correct answer. Here examiner says that Bipolar world, that we witnessed during cold war, was more peaceful than the pre-cold war era's multipolarity.

As a rule of thumb, world becomes violent moving towards multipolarity. Multipolar world is violent due to various prominent powers and varied interests of these powers make it a violent system.

The answer should have discussed bipolarity and multipolarity ,and should have also discussed why multipolar world was more violent than bipolar world. You should have mentioned examples from ancient Europe and from cold war era. Further, you should have discussed the emeriging status of multipolarity and it's affects on peace of contemporary world.