What is the difference between dynamic open market operations and defensive open market operations?

What is the difference between dynamic open market operations and defensive open market operations?

1. What is the difference between dynamic open market operations and defensive open market operations? What are the differences in the ways these two types of open market operations are carried out?
2. What advantages do open market operations have over other policy tools?
3. What is quantitative easing? Why did the Fed use it during the financial crisis of 2007–2009?
What is the difference between dynamic open market operations and defensive open market operations?