Scrum defines one team — the Scrum Team — with three accountabilities: Product Owner, Scrum Master, and Developers. There are no sub-teams or hierarchies; the whole team is accountable for creating value each Sprint.
The three roles
PRODUCT OWNER Owns the Product Backlog and maximizes product value.
Decides WHAT gets built and in what order.
SCRUM MASTER Serves the team, coaches Scrum, removes impediments,
and facilitates events. Owns the team's effectiveness.
DEVELOPERS The people who build the Increment each Sprint.
Decide HOW the work gets done; self-managing.
