By 1999, after the clean water act had been passed in 1970 the percentage of us surface waters safe for fishing ans swimming increased from 36 percent to

The terrestrial planets are characterized by having a a.) silicate core b.) iron-rich silicate core c.) iron-rich metallic core d.) none of these

How did alexander fleming’s research solve a societal problem? he developed ways to treat inherited diseases. he advocated for regular hand washing to kill germs. he discovered a new type of medicine that could treat infections. he discovered the cause of mad cow disease, an emerging disease.

This rapid change in species that rarely leaves behind fossil evidence is referred to as