Natural resources are scarce, and property rights are very important. Because the property rights are clear, people will no longer be overloaded to graze. People who have seen the agriculture and animal husbandry areas in developed countries know that barbed wire is used to divide pastures, which is completely a gentleman boundary. You can't stop the villains. But in a legal society, this kind of boundary between gentlemen and villains has legal authority. No wonder there is a book that says the barbed wire is one of the ten greatest inventions of human society in the nineteenth century. What does this not mean? ['The division of property rights must be guaranteed by law.', 'Barbed wire works only in a legal society.', 'Law can restrain gentlemen but not villains.', 'Clear property rights can prevent overexploitation of natural resources.']