1. When developing a requirements model using UML, a primary artefact that is created is the Use Case. Within the context of requirements modelling with UML, answer the following questions: (i) Briefly explain what is meant by the term Use Case. [3 Marks] (ii) Outline three roles that Use Cases can perform. [6 Marks] (iii) Using a diagram to illustrate your answer, describe four UML notation elements used within a Use Case diagram and briefly explain each one you identify [12 Marks] (iv) Describe what you would consider to be the three most important aspects of documenting a Use Case. In your answer, ensure you provide an example of each. [12 Marks]