Cross-functional teams are optimized to work on one technical layer of a system only (e.g. GUI, database, middle tier, interfaces).

According to the Scrum Guide1, the Development Team consists of professionals who do the work of

delivering a potentially releasable Increment of “Done” product at the end of each Sprint.

Development Teams are structured and empowered by the organization to organize and manage

their own work. The resulting synergy optimizes the Development Team’s overall efficiency and

effectiveness. Cross-functional teams have all competencies needed to accomplish the work without

depending on others not part of the team. The team model in Scrum is designed to optimize

flexibility, creativity, and productivity.

Reference: Scrum Guide