A mathematical process of coding information so that only the intend user can read it

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

The song about casey jones a railroad engineer who gives his life on the job would most likely gall under the folk song category of? a-work song b-nonsense song c-religious song d-ballad

Iam trying to get my google account back for school and business, can someone ?