Please answer by T for True and F for False:

1)In a sequence diagram, the activation box (i.e. the white vertical bar overlaid on the lifeline of one object) represents the time when a method of the corresponding object is on the execution stack.

2)In OO design, composition is commonly used to represent a collection of other abstractions or to break down complex functionalities and delegate them to specialized classes.

3)To copy an object polymorphically, one common way is to use the copy constructor, which allows the client to pass the object as an argument.

4)In Java, the clone() method is defined in the Object class. When implementing the Cloneable interface, you should override the clone method in your own class.