What are the four reasons that we did nothing to stop hitler

At the beginning of the war, why was hitler allowed to continue his aggression without resistance from other european countries

The current population of a city can be represented by "p." the population is expected to increase by 6.5% next year. write an expression in simplest form that represents the expected population next year.

What was one major cause of worldwide conflict during the first decade of the 21st century?