Which of these statements about pollution tolerant species is true?

Pollution tolerant species are organisms that have adapted to survive in environments with high levels of pollution or lower water quality. These species possess certain physiological and behavioral traits that allow them to thrive where more sensitive species may not survive. They often include certain types of fish, invertebrates, and plant life that can tolerate higher concentrations of pollutants such as heavy metals, nutrients, or sedimentation.

The ability of these organisms to live in polluted waters does not diminish their ecological importance; they can indicate levels of environmental stress and can be used as bioindicators by researchers to assess water quality. Therefore, the statement that these species can live in polluted waters is accurate and reflects their survival mechanisms in compromised environments.

In contrast, claims that pollution tolerant species can only survive in clean water, can enhance water quality, or are always at the top of the food chain do not align with the fundamental characteristics of these organisms. They are not adapted for pristine conditions and do not contribute significantly to improving water quality in the way some other species, like filter feeders, might. Furthermore, being pollution tolerant does not necessarily mean these species occupy a high trophic level; they can be found in various roles within the food web.