a secondary source could be someone that maybe discovered the body or is doing evaluations to see why or how he died, like a doctor for instance it would be a secondary source doctor was not there and he did not watch if he wrote about it then that would be a secondary source! : ) < 3 hope this !
d. they built cities and fortresses on the highlands of the andes mountains.
there has been much writing on this vary topic with a wide range of responses.
the broad thinking is that world war 2 could have been prevented, to a point. efforts could have been made to contain the advance and expansion of the nazi regime but ultimately there would have been small wars every few years to contain the nazi regime.