The Scrum Master observes the Product Owner struggling with ordering the Product Backlog. What is an appropriate action for the Scrum Master to take?

If two Scrum Teams are added to the development of a product that previously had only one Scrum Team, what will be the immediate impact on the productivity of the original Scrum Team?

A Scrum Team has been working on a product for nine Sprints. A new Product Owner comes in, understanding he is accountable for the Product Backlog. However, he is unsure about his responsibilities.
Which two activities are part of the Product Owner role according to Scrum? (Choose two.)