Question

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? semiconductor conductor superconductor insulator

Explanation:

Selenium is a well - known semiconductor. Semiconductors have conductivity that can be controlled by adding impurities (doping), which is what Dr. Eriksson is doing (adding a certain number and type of atoms to control conductivity). Conductors have high and relatively fixed conductivity, superconductors have zero resistance (a very specific property not indicated here), and insulators have very low conductivity that is not easily changed by simple atom addition in this context.

Answer:

semiconductor