How do firms choose their overhead cost assignment? How do firms choose optimal cash strategy determined by critical production activities that create and capture values? What is the nature and function of expense assignment? What are reasons for expense indicators or cost drivers? What are some policy implications of the Activity Based Costing in formulating effective cost assignment and spending budget strategies? Macroeconomics' need for government intervention ' Hybrid cars, which add an internal combustion engine to pure electric vehicles, aim to reduce the pollution of cars and improve the mileage of pure electric vehicles. Hybrid vehicles have serial and parallel structure.