What is an ion? a. a group of two or more atoms that acts like one atom b. a compound that contains two elements c. a particle in the nucleus of an atom that has no charge d. an atom or particle with a positive or negative charge

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.