Deal with the production, distribution, and consumption of goods and service, or the material welfare of humankind, and the analysis of the commercial activities of a society. Particular issues include the costs and benefits of alternative environmental policies to deal with e. g. air pollution, water quality, toxic substances, solid wastes, loss of biodiversity, and global warming. Eg what is the best way to address the issues. Our society is heavily focused on growth (e. g. gdp growth) How do we get the most clean per dollar. Ecological: enough is best - economic growth leads to environmental degradation and inequality in wealth. Enough is enough look for optimal level of population and economic activity, which lead to sustainable and not perpetual growth. Economists fo this balancing formally though cost-benefit analysis. If one factor of production is increased while others remain constant, the marginal benefits will decline and, after a certain point, overall production will also decline.