Ecologists study the relationships between living organisms and their environment.

Which of the following pieces of evidence is not useful to an ecologist constructing an explanation that humans are negatively impacting a local ecosystem?


The concentration of algae in the water has increased due to the chemical runoff of nitrates from local farms.


The pH of the water has become acidic due to pollution from local industries.


The local government has imposed regulations to restrict the use of fertilizers and pesticides.


The population of a fish species has declined rapidly due to overfishing.