When trying to understand the Agile processes, you will find them being actually a general approach to software development. All agile methods are based on teamwork, frequent delivery of working software, close customer collaboration and the capability of quickly respond to change.
Scrum is just one of many others in Agile: XP, DSDM, TDD, BDD, Kanban etc. So, many teams that use Scum can employ other methodologies (part of them enumerated above). The flexibility of the agile process is a large part of its appeal.
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