The Following Is the Best Example of a Synergistic Effect

The following is the best example of a synergistic effect in the Great Lakes: ________.

A) Phosphorus deficiency limiting fish growth in some areas of the Lakes and excess phosphorus in other areas of the Lakes
B) The collective impact of urban and industrial development around the shores of Lake Erie
C) Canada and the United States signing the Great Lakes Water Quality Agreement to work together to improve water quality in the region
D) The invasive zebra mussel that converts phosphorus into a form easily used by aquatic plants such as algae, thereby increasing the impacts of eutrophication