Identify one cause of these nationalistic conflict?

Colonialism, Cold-War, ethnic tensions

Explanation:

There are a variety of reasons that 20th-century nationalist conflicts occurred including colonialism, the Cold-War, ethnic tensions, and others. However, many were fought for independence against the country's colonial power and in the wake of this, there were often internal conflicts as well. The results of these conflicts were varied and range from genocide to the creation of new states, to man other outcomes.

Good luck!