What is a strong topic sentence for "what is geography"?

1. how did conditions in germany and europe at the end of world war i contribute to the rise and triumph of nazism in germany? 2. how did the german government under nazi rule build support among the german people? 3. how did nazi germany gradually isolate, segregate, impoverish, and incarcerate jews and persecute other perceived enemies of the state between 1933 and 1939? 4. how did the nazis lead germany to war in europe and, with their collaborators, kill millions—including systematically murdering six million jewish people? 5. why is learning about the holocaust important? so we don’t repeat history.