Costs and/or benefits may, in some markets, spill over onto people outside of the market transactions - thus, the externality. Example: some are positive (my neighbor who lives to the left of me, has a flower garden that improves my quality of life and he's done all the work) and some are negative (my neighbor to the right of me lowers the quality of my life with the two broken down cars he keeps on his front lawn). Noting what has been mentioned above, take a positive externality or a negative externality and explore it in detail. Examine the role of social costs and benefits, private costs and benefits, what role, if any, can the government or even the private sector play in correcting the externality, is there a free rider problem associated with it and can it be corrected? As we attempt to correct for the externality what additional tradeoffs may the private and/or pubic sectors make?

can help me construct a graphs to help reinforce and bolster the argument?