nuclear power plants hydroelectric power plants coal-burning factories noncommercial farms
I gave my students this multiple choice question: Certain lakes in the northeastern part of the United States have had decreases in pH levels, causing the deaths of many fish. What is the most likely reason for this change in pH levels?

Only one answer is correct among these 4 choices:
- nuclear power plants
- hydroelectric power plants
- coal-burning factories
- noncommercial farms

Could you tell me which one is correct?

coal-burning factories