What is the most important discovery of the stone age people and why

In the old stone age, or paleolithic era, the most important discovery was that you could chip stone in such a way as to produce a sharp edge that could be used to cut things. All progress in the stone age depended on this. There is not too much you can do in the way of making things, without first having some kind of edge to cut things with. In the new stone age, or neolithic era, the most important discovery was that you could plant crops to create a more reliable food source. Even to this day, in the 21st century, agriculture remains the foundation of human society as we know it. We would be unable to feed more than a very small fraction of the world’s current population of 7 billion people, without the use of agriculture. If we were to rely on hunting and gathering, it is possible that the world could support about 50 million people at most.