The authors distinguish between controllable and uncontrollable factors that influence the demand for a product. One of the controllable factors on their list is advertising --- do you agree with this classification? Companies can control the amount they spend on advertising, but can they control the impact of their ads on the demand curve? If you agree with the classification, please explain your reasons. If you do not agree, can you provide an example in which a prominent advertising campaign did not have an impact on consumer demand? What about examples of ad campaigns that backfired and actually reduced the demand for their product?