Question

which of the following was most responsible for the positive turn - around in water quality of lake washington near seattle, washington? adding additional fertilizers to the lake making the lake off - limits to use by humans stopping the flow of human sewage into the lake adding more human waste to the lake

Explanation:

To determine the correct answer, we analyze each option:

• Adding fertilizers would likely cause eutrophication and worsen water quality, so the first option is incorrect.
• Making the lake off - limits to humans is not the main reason for the water quality improvement of Lake Washington. The key issue was sewage pollution.
• Lake Washington's water quality deteriorated due to sewage discharge. Stopping the flow of human sewage into the lake would reduce pollution (like nutrients and pathogens from sewage) and improve water quality, which matches the historical solution for Lake Washington.
• Adding more human waste would obviously degrade water quality, so the last option is incorrect.

Answer:

C. stopping the flow of human sewage into the lake (assuming the options are labeled A, B, C, D with A: adding additional fertilizers to the lake, B: making the lake off - limits to use by humans, C: stopping the flow of human sewage into the lake, D: adding more human waste to the lake)