What is the similarity between primary source and secondary source?

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

Was the amassing of men, equipment, and supplies for the 1944 invasion of europe. operation varsity operation nordwind operation dragoon operation overload operation torch

Hey!me its for an important test! ! which issue during the progressive era would most likely have united mary harris "mother” jones and lewis hine? a) ending child labor b) regulating monopolies c) using photography to expose poor working conditions d) exposing the lack of jobs available for untrained laborers