Worksheets on OCR GCSE Economics 3.8 Limitations of markets, covering 3.8.1 Positive and negative externalities, 3.8.2 Policies to correct externalities, 3.8.3 Impact of externality policies, and 3.8.4 Costs and benefits of externality policies, with answers. Print them, or work through one on screen. Write your working straight onto the paper and Genie marks it question by question against the mark scheme.