The transition from hunting and gathering to agriculture is not necessarily a one way process. It has been argued that hunting and gathering represents an adaptive strategy, which may still be exploited, if necessary, when environmental change causes extreme food stress for agriculturalists. In fact, it is sometimes difficult to draw a clear line between agricultural and hunter-gatherer societies, especially since the widespread adoption of agriculture and resulting cultural diffusion that has occurred in the last 10,000 years.[citation needed] This anthropological view has remained unchanged since the 1960s.[clarification needed][citation needed]

Answer this question, if possible (if impossible, reply "unanswerable"): What situation can cause food stresses that make hunting-gathering necessary?
environmental change