An example of a grad-school level question?
Alex looked at an electric toothbrush that had a plug with three metal prongs. Why are these prongs made out of metal?

An example of a grad-school level question?
Louis Pasteur discovered that the bacteria in a substance can be killed by heating the substance for a short period of time. Which of these practices benefited most from Pasteur's discovery?

An example of a grad-school level question?
An element is identified by

An example of a grad-school level question?
Which statement describes all matter?