Ethicist: On average, animals raised on grain must be fed sixteen pounds of grain to produce one pound of meat. A pound of meat is more nutritious for humans than a pound of grain, but sixteen pounds of grain could feed many more people than could a pound of meat. With grain yields leveling off, large areas of farmland going out of production each year, and the population rapidly expanding, we must accept the fact that consumption of meat will soon be morally unacceptable. Which one of the following, if true, would most weaken the ethicist's argument? ['Often, cattle or sheep can be raised to maturity on grass from pastureland that is unsuitable for any other kind of farming.', 'Although prime farmland near metropolitan areas is being lost rapidly to suburban development, we could reverse this trend by choosing to live in areas that are already urban.', 'If a grain diet is supplemented with protein derived from non-animal sources, it can have nutritional value equivalent to that of a diet containing meat.', 'Nutritionists agree that a diet composed solely of grain products is not adequate for human health.']