Scrum question

Hi,

I hope anyone can help with following questions/scenario:

1. What does "cross-functional team" mean by definition?
Does it mean that the development team consists of cross-skilled individuals with flexible roles (=a designer can also be a developer or a tester)?
Or
does it just mean that the development team consists of members of certain departments e.g. a business analyst who is ONLY skilled to make a business analysis and not doing testing?

2. What can/must the Scrum Master do, when the Product Owner is not collaborative? e.g. the PO is always busy and has no time to adjust or review the Product Backlog. Teaching him of Scrum rules has no result. Is it possible that the development team members elect a new/another PO? May a development team member be elected as a new PO?

Thanks for your help!