After which atomic number is every element radioactive and can form through artificial transmutation?

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

Compare and contrast physical changes with chemical changes.

Using data from seismic waves, geologists have learned that earth’s interior is made up of several