Developing strategies for sustainable competitive advantage, implementing them, and Adjusting the strategies to respond to new environmental requirements are a continuing Process. It begins by defining the mission of the business. Managers monitor the market and competitive environment. The corporate mission may, over time, be changed because of problems or opportunities identified by monitoring. An important part of business strategy in a firm made up of more than one business area (e.g., different products and/or markets) is managing the portfolio of business units. These units often have different • objectives and strategies. The strategy for each unit indicates how it will fulfill its assigned role in the corporation. Underlying each unit's strategic plan are functional strategies for marketing, finance, research and development, and operations