Part of the definition of MVC (shown in Figure 2.5) is that the controller updates model objects. The book says “GeoQuiz’s model layer consists of the TrueFalse class”. The controller layer is in QuizActivity. Where does the controller update the model? TrueFalse doesn’t contain any state, so I don’t see how it could be updated, unless the index of the current question (mCurrentIndex) was moved from QuizActivity to TrueFalse.