An example of a grad-school level question?
A student finds a round, smooth pebble on a beach. Which action made the pebble smooth?

An example of a grad-school level question?
Which characteristic is shared by Earth and the Moon?

An example of a grad-school level question?
What most likely happens to soil when crops are not rotated from year to year?

An example of a grad-school level question?
Solids that are combined together and maintain their physical properties are best labeled as a