Is Scrum master responsible for product backlog?
The product backlog is a list of work that the team needs to do. The Scrum master helps the product owner refine and maintain the product backlog using the information gathered from the daily stand-up meetings.
Who is responsible for updating the sprint backlog?
During the Scrum sprint, team members are expected to update the sprint backlog as new information is available, but minimally once per day. Many teams will do this during the daily scrum.
Who makes the final decision on ordering the product backlog?
The product owner has the final decision on prioritizing the product backlog.