what is the correct answers?

Question 15 Not yet answered Marked out of 1.00 P Flag question Structured things define the static part of the model. Which of the following is not a structured thing? O Interface O Package O Use case O Class Question 16 Not yet answered Marked out of 1.00 P Flag question Which models in Booch methodology describes and discusses the classes & objects in the system Logical model Physical model O Static model O Dynamic model Question 17 Not yet answered Marked out of 1.00 P Flag question A minimal set of attributes that uniquely identifies object or link is--- -: Candidate Keys O Aggregation Meta data O Polymorphism