Answer:
WWII
Step-by-step explanation:
We can use process of elimination.
Rice: While everyone needs to survive, not everyone has access too or eats rice, therefore it isn't universal.
Vietnam War: This war didn't contain every single country, therefore it isn't universal.
Suffering in War: All countries do not suffer in the same way, a countries suffering often depends on the time period of the war and seeing as how all wars take place in different years, this is not universal.