Plants absorb sunlight through Photosynthesis. Which characteristic of life is this an example of?

It is "The ability to process energy."

If for some reason that's wrong, it is "The sensitivity/response to environment."

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.