When does a Sprint conclude?

The Scrum Team must choose at least one high priority process improvement item, identified during the Sprint Retrospective, and place it in the Sprint Backlog.

Who is on the Scrum Team?

The Developers should have all the skills needed to:

The timebox for the Sprint Planning event is?

Which Scrum events are timeboxed?

What does it mean to say that an event has a timebox?