PLZZ help ( I’ll give u brainliest ) :D

antartic fish have antifreeze proteins in their blood

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.

i think the answer is a.keratin is the pigment responsible for skin color.