I believe the answer is Integumentary, Hope this helps ")
        
             
        
        
        
The answer to that question would be C. temperature
        
             
        
        
        
Increasing levels of chemicals in freshwater is attributed to fertilizers because in agriculture most of the farmers use fertilisers for a better crop, but those chemical fertilisers eventually flow into the water bodies and gets mixed with them. Therefore harming it and being an attribute.
        
             
        
        
        
C) Mitochondria should be it