An example of a grad-school level question?
Toads lay their eggs in ponds. Tadpoles hatch from the eggs and eat the plants floating in the pond. Which resource is most important for toads to survive?

An example of a grad-school level question?
The abundance of a mineral at the surface of Earth most likely depends upon the

An example of a grad-school level question?
Which action most likely causes large rocks to become smaller pieces of rock?

An example of a grad-school level question?
Which of the following animal features most helps the animal move around in its habitat?