(I)It has been hypothesised that the rise in mobile phone usage replaced smoking among teenagers. (II) Nevertheless researchers could not find any connection between these two subjects. (III) Mobile phones were once reserved for the very wealthy. (IV) In fact, it has been found that teenagers who use their phones regularly were more likely to be daily smokers. (V) Also, the theory that the pay for phone cards competes with cigarettes has been proved to be incorrect.