God gave everything to humanity. Satan rebelled against God and went to destroy the purity of humanity. God warned Adam and Eve that its all for them, the paradise and beauty, but they must not eat from one tree.
Satan deceived them and now we are paying the price as we no longer are holy and pure in the eyes of God, but because God loves us He has given us a chance through the grace of Jesus, to become pure and enter His Holy Kingdom for eternity. Adam and Eve lived many years and had many children says the bible. It many ancient texts it is mentioned they had 30 sons and 30 daughters.
In another it says cain marries 2 of his sisters. The bible does say they had many children. They lived for many years why wouldn't they.
There was no incest law by God at that time.
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.