It looks like your project is seriously messed up. You don't seem to be linking with the Foundation framework or the UIKit framework.
I had a similar error and this solved my problem : Click "TARGETS" > Build Phases >Link Binary With Libraries > Click "+" > CoreData.framework. > Add.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.