An example of a grad-school level question?
Which involves the greatest variety of cell types?

An example of a grad-school level question?
To which organ system do the esophagus, liver, pancreas, small intestine, and colon belong?

An example of a grad-school level question?
In the human body, what part of the central nervous system connects with other nerves outside of the central nervous system?

An example of a grad-school level question?

Improvements in geological observation technologies have made it easier for scientists to locate resources in Earth's crust. These technologies have allowed for an increase in availability of which resource?