How are World War I and World War 2 the same and how are they different?

they are similar because their both wars and their different because World War 1 came first and World War 2 came second

AnswerThey were similar in the obvious respect that they were both global wars, and fought with the highest level of industrial technology available at the time.

They were different in that WW1 was an imperial war of the type seen many times before, although it was by far the largest. By WW2 Imperialism was on the way out, and it was a clash of ideologies (democracy, fascism, and communism) which vied to replace it.