What was the main pullutant (nutrient) that was mentioned in this article? A) Nitrogen
B) Oxygen
C) Phosphorus
D) Potassium

The dashed segment of the plotted experiment in the graph in the lesson is called an

The us and canadian governments are doing all of the following to combat environmental problems except a. encouraging the use of public transportation b. enacting clean water policies c. requiring emissions testing d. limiting animal populations in some regions

All of the following occurred due to the invention of the railroad except