1. The population of fish and amphibians in a lake more than 100 miles downward from a coal-fired power plant suddenly began to decline. Biologists sampled the water in the lake and found that it had a pH of 2.4. What conclusions could the biologists draw from their finding? a. Acid rain that had fallen on the lake had to have come from a pollution source close to the lake. b. Pollutants from the power plant could be making the lake water too alkaline (basic) to support life. c. The pH of the lake water was normal, so the decline in fish and amphibian populations had some other cause. d. The lake water had become very acidic, which could be linked to the emissions from the distant power plant.