Question 4 (a) Give a description of the waterfall process model. In your answer you should describe the main tasks that are conducted, and the order in which they are carried out. You may want to include a diagram to clarify your answer. 17 marks] (b) Describe one advantage and one disadvantage of adopting the water fall rocess model in comparison to other proces models. 4 marks] (c) Describe the key principles which underlie Agile software develop- ment. [8 marks] (d) Risk management is an important part of software project planning. Describe what is meant by a risk and give two examples of risks which could seriously affect a project. 4 marks]