Which of these leads to competition between two species?
a) an overlap in the two species' niches
b) an increase in genetic diversity in one species
c) the extinction of a predator species
d) an increase in available recources
answer is a^^

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.

answer; i believe the answer is (polygenic inheritance;