An example of a grad-school level question?
Natural selection cannot occur without

An example of a grad-school level question?
A car skids along the road and smoke appears to be coming from under the tires. The heat that produces the smoke is caused by

An example of a grad-school level question?
Which BEST explains why green marine algae are most often restricted to the top 100 meters of the ocean?

An example of a grad-school level question?
All these statements concerning galaxies are accurate except