What characteristic should requirement possess?

The requirement should be Complete

Who is actually the Scrum Master?

scrum master coach

The Scrum Master helps the team to be productive and use they creativity in order to deliver done, working software.

The main point here is that the Scrum master leads the team, but not command the team

The Scrum Master is a Coach. He is not a boss. The team members doesn’t need to report to the Scrum Master.
The Scrum Master is not a manager and doesn’t order to do anything. He is a leader and he need to figure out how to lead the team.

3 Levels of requirements in Agile development

Requirement levels

In Software Development Requirements have 3 levels:

Business requirements (Vision and Scope document)
– expanded description of customers business
– business point of view requirements
– functionalities which should be made in our application