The more frequently bacteria are exposed to antibiotic, the more quickly the bacteria will develop resistance to the antibiotics. A columnist for the Wall Street Journal observes: “Each parent will press a pediatrician for a dug if there’s any chance it will cure a child. Yet if every parent and pediatrician does the same, they will speed the evolution of drug-resistant microbes. And what drug company will enlist its marketers to prod doctors to prescribe its antibiotics less?” Briefly discuss in what sense antibiotics can be considered a common resource.