What are the two key concepts for this section? Explain how streams can cleanse themselves of oxygendemanding wastes and how this cleansing process can be overwhelmed. Describe the varying states of...

What are the two key concepts for this section? Explain how streams can cleanse themselves of oxygendemanding wastes and how this cleansing process can be overwhelmed. Describe the varying states of stream pollution in more- and less-developed countries. Give two reasons why lakes and reservoirs cannot cleanse themselves of biodegradable wastes as readily as streams can. Distinguish between eutrophication and cultural eutrophication. List three ways to prevent or reduce cultural eutrophication. Explain how seasonal dead zones form in the Gulf of Mexico. Describe the pollution of the Great Lakes and the efforts to reduce this pollution.