He handed out all of the tests and went back to his desk to wait. Once the test was over the students all handed the tests back in. The next class the professor handed the tests back out. Students are asked to blot ink in their exam books, close them and turn them in. The professor opens the books and assigns the first grade that comes to mind.
All students get the same grade they got last year.
Grade is determined by G-d. All theoretical physics is really mathematics. All theoretical chemistry is really physics. All theoretical biology is really chemistry. YOUR grade is an object in a class of its own.