In 2014, the city of denton, texas, passed a local initiative that prohibited "fracking" — the practice of breaking up rocks underground to release natural gas — out of concern over its environmental effects. in response, the texas state legislature passed a bill in 2015 declaring that only the state government could regulate the oil and gas industry in any major way. the 2015 law prohibited all municipalities in texas from regulating fracking. why might municipal home rule not affect cities' powers in this case?