Code is easier to read and maintain is known as ___________? 

External correctness is performed in __________?

How to confirm the requirements are covered in models? 

Validation checks for consistency, correctness and completeness?

Messages between objects shown as labelled sequence arrow placed near the links in which diagram?

Sequence diagram is the most common kind of interaction diagram, which focuses on the message interchange between a number of ____________. 

Swimlanes are used to denote the ___________ is associated with the responsibility.

Which event is caused by the satisfaction of a Boolean expression? 

To start a use case, ________ are events that initiate the first steps of a scenario.

How one use case can invoke behavior defined by another use case?