Dr. Eriksson is working on a material called selenium. She is adding a certain number and type of atoms to the selenium, which will control its conductivity. Selenium is most likely what kind of material?

Selenium is a semiconductor, whose conductivity can be changed by adding small amounts of other atoms (a process called doping). This makes “semiconductor” the best choice; ordinary conductors and insulators do not have their conductivity controlled in this characteristic way.

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