Ten thousand years ago many communities in western Asia stopped procuring food by hunting and gathering and began instead to cultivate food. Archaeological evidence reveals that compared to their hunter-gatherer forebears, the early agricultural peoples ate a poorly balanced diet and had diet-related health problems, yet these peoples never returned to hunting and gathering. Which one of the following, if true, most helps to explain why the agricultural peoples of western Asia never returned to hunting and gathering? ['Both hunter-gatherers and agriculturalists sometimes depended on stored and preserved foods instead of fresh foods.', 'An increase in population density at the time required a higher food production rate than hunting and gathering could provide.', 'Thousands of years ago similar shifts from hunting and gathering to agriculture occurred in many other parts of the world.', 'The plants and animals that the agricultural peoples began to cultivate continued to exist in the wild.']