What information should be public domain and why?

The north and south regions had very diferent economies in the 1800s.

Need asap write a short paper describing the history and differences between six sigma, waterfall, agile, and scrum models. understanding these models can give you a good idea of how diverse and interesting it development projects can be. describe what the rationale for them is and describe their key features. describe the history behind their development. at least 400 words

What is the term for water wave that is created by an underwater earthquake