Which of the following was a cause of world war 1 1) religious intolerance
2) extreme nationalism
3) desire for colonies
4) competition between communism and fascism

(2) Extreme Nationalism
Explanation: because at this point of time, each country wanted to feel proud and show others that they are far more superior than others. For example, nationalism in Germany grew so much that people starting more for the war and started manufacturing more weapons related to war … therefore some countries faced so much nationalism that the war itself was extended. Not religious intolerance because that was the reason for wars in more times like the Crusades or about in the 900-1250… In circa 1800-2000 wars happened due to nationalism, and the powers of making more money than other countries for example the factory system and developing more and efficient machinery. Not desire for colonies because that was a thing to cause war back than before 1700. Not competition between communism and fascism because those were the reasons of i believe of world war 2 and the cold war! Thanks for reading … :)