Supply
Government policies: When the government intervenes in the market, it can do so by subsidizing or taxing the production of the good. When a subsidy is provided, it lowers the marginal cost of producing the good, thus allowing firms to produce more for the same amount of resources used, thereby increasing supply. When a tax is used, the marginal cost of producing the good increases. Firms now produce lesser for the same amount of resources used and supply becomes lesser.