positive and negative externalities

write a 3 page paper in which you identify and discuss 3 externalities they can be positive or negative. conclude why an externality might exist in the situation that you described, and determine the solution that might mitigate these particular externalities. Analyze the different stakeholders (i.e., the government, three (3) affected parties) that are involved in the externality, and identify their roles are in regard to the externality.