An example of a grad-school level question?
Crows are found throughout many parts of the world. They are black birds with excellent hearing. In the wild they live for six to seven years. Some crows in Japan open hard-shelled nuts by dropping them in front of moving cars. Which of these is a learned behavior?

An example of a grad-school level question?
Rocks that contain fragments of bones, shells, and plant remains are most likely

An example of a grad-school level question?
Which is the best example of a pure substance?

An example of a grad-school level question?
During which season of the year would a rabbit's fur be thickest?