Final answer:
The correct answer is option C. The best labeling for the axes of a graph describing the effects of dam removal on both salmon populations and the aluminum industry in the Pacific Northwest is 'salmon' and 'aluminum.' This captures the ecological benefits for salmon and the economical downsides for the aluminum industry due to increased energy costs.
Step-by-step explanation:
In the context of the Pacific Northwest, where a hydroelectric dam is being removed to enhance salmon populations, the question pertains to how best to label the axes of a graph representing the scenario described. Considering the information provided on the impact of dam removal on salmon populations and the subsequent effects on the aluminum industry through unemployment due to the loss of cheap hydropower, the axes of the graph would be best labeled as 'salmon' and 'aluminum.'
The dams have provided a source of inexpensive electricity which is crucial for the aluminum industry, however, they also obstruct salmon migration, which is vital for their population growth and the overall health of the ecosystem. The removal of the dams to increase salmon populations can thus negatively impact the aluminum industry by removing their source of cheap electricity.
Therefore, the axes reflecting the relationship between the two industries affected are best labeled as 'salmon' and 'aluminum.' The correct answer to the student's question is: C. The axes are best labeled salmon and aluminum.