What is the difference between margin and padding?
Margin defines how much blank space outside of a HTML element, while padding defines blank space on the inner side of a HTML element.
Why should you always mark your base classes as abstract.
A base class by itself only represents common traits and logic of other classes, so you should prevent a base class from being instantiated directly.
What is the benefit of wrapping a database connection in a "using" statement?
The benefit is always knowing that your database connection is closed and properly disposed when you are done with it without having to wrap the call in a try-finally block.