What is difference between use case and use case diagram?

A use case outlines a specific goal and how to achieve that goal A use case diagram is a graphical representation of system users(actors), use cases, and the system (subject) to which this set of use cases applies.

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.