Explain the similarities and differences between an adaptive project management life cycle model and an extreme project management life cycle model

Explain the similarities and differences between an adaptive project management life cycle model and an extreme project management life cycle model. Discuss the conditions that would suggest the use of one model over the other.you should choose examples from your own experience or find appropriate cases on the Web that you can discuss. Credit will be given for references you make to relevant examples from real companies. Please cite and reference all your outside sources as per the Harvard Referencing System.