My answer is <span>The development of new stone tools about 12,000 years ago brought the period called the Neolithic Revolution. Those new tools caused the extinction of numerous large mammals. With that extinction, the hunting and gathering culture could no longer continue as it had. It became necessary to find new sources of food. The sharper tools of the new stone age made it possible to add new vegetable sources to the diet. Trees could be cut back and the fruit at the ends of the branches could be harvested. Since old growth doesn't bear fruit, the process of pruning trees would also make them more useful. The stone tools also made agriculture possible. Fig cultivation began about this time around Jericho. Maybe some day, indications will be found of other plants cultivated about this time.</span>
