An example of a grad-school level question?
Sulfur scrubbers are devices installed in coal-fired power plants. Sulfur scrubbers reduce the emission of sulfur dioxide. What environmental problem are sulfur scrubbers most likely trying to address?

An example of a grad-school level question?
The prairie grass ecosystem once had a deep layer of topsoil which was protected by the grasses that covered it. Removal of these grasses for farmland is causing the soil to be eroded mainly by

An example of a grad-school level question?
In humans, the digestion process begins in

An example of a grad-school level question?
Brittany pedaled her bicycle quickly on a level surface. When she stopped pedaling and coasted, the bicycle slowed and came to a stop. What happened to the energy of the moving bicycle as it coasted to a stop?