A student's biology professor announces an exam next week on birds. "You will have to know everything about every type of bird there is," he says. The student spends the week studying beaks, wings, and feathers of dozens of bird species.

On the day of the exam, the professor has a table with five paper bags on it. Under each bag is a model of a bird. The professor lifts the first bag to reveal only the legs, and tells the class to write down the type of bird. The student groans, because she can't even guess the type of bird. When the professor gets to the third bag, the student stands up, walks up to the table, and throws her crumpled test paper onto the table. She says, "This is the most ridiculous test I have ever seen, and you are an IDIOT!"

The professor says, "Just hold it right there, what is your name?"

The student raises her dress to the knees and says, "You tell me!"