An example of a grad-school level question?
What is taken in by the leaves of a tree so it can make its own food?

An example of a grad-school level question?
Which of the following eras is known as the "Age of Mammals"?

An example of a grad-school level question?
Falling and rising air and water molecules inside of clouds are believed to be factors in the formation of lightning. Which kind of energy transfer is taking place to cause this weather phenomenon?

An example of a grad-school level question?
What causes a meteoroid to glow as it falls through the atmosphere of Earth?