40. (a) Why is it essential to make periodic reviews of information systems projects? (b) Explain four characteristics of a well-designed information system. (c) Briefly explain the three fundamental components of an expert system. 41. (a) Explain the term Decision Support System. (b) Explain four characteristics of a Decision Support System. (c) Describe four components of a Decision Support System. (d) State two advantages of an Executive Support system (ESS). 42. (a) Explain three functions of management. (b) Identify and state the function of each of the different levels of management. (c) Outline four characteristics of useful and effective information. (d) Explain the importance of management support in project implementation.