Why do old undecided questions showing an answer in the list open up with no answer?

It's a bug. I asked @jeffhoard about it yesterday actually. If you keep encountering it, use the report button to report the bug and the staff will get on it.

I think you may have discovered the footprints of the Mahalo Ninjas.... when they suspect that a question has been answered by spammers, idiots, or in some other violation of the Mahalo code they leap into action and apply a swift kick to the head making the answer vanish in a cloud of Ninja smoke..

I always thought it happened when a user has answered questions that have been reported and removed, or when a user account had been banned along with their answers. However, after seeing that @chris has already had a different answer from Jeff I guess I'm wrong! Still posting this though because I'm sure I might be a little bit right... ;).

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.