<P> The very earliest Acheulean assemblages often contain numerous Oldowan - style flakes and core forms and it is almost certain that the Acheulean developed from this older industry . These industries are known as the Developed Oldowan and are almost certainly transitional between the Oldowan and Acheulean . </P> <P> In the four divisions of prehistoric stone - working, Acheulean artefacts are classified as Mode 2, meaning they are more advanced than the (usually earlier) Mode 1 tools of the Clactonian or Oldowan / Abbevillian industries but lacking the sophistication of the (usually later) Mode 3 Middle Palaeolithic technology, exemplified by the Mousterian industry . </P> <P> The Mode 1 industries created rough flake tools by hitting a suitable stone with a hammerstone . The resulting flake that broke off would have a natural sharp edge for cutting and could afterwards be sharpened further by striking another smaller flake from the edge if necessary (known as "retouch"). These early toolmakers may also have worked the stone they took the flake from (known as a core) to create chopper cores although there is some debate over whether these items were tools or just discarded cores . </P> <P> The Mode 2 Acheulean toolmakers also used the Mode 1 flake tool method but supplemented it by using bone, antler, or wood to shape stone tools . This type of hammer, compared to stone, yields more control over the shape of the finished tool . Unlike the earlier Mode 1 industries, it was the core that was prized over the flakes that came from it . Another advance was that the Mode 2 tools were worked symmetrically and on both sides indicating greater care in the production of the final tool . </P>

Which of the following characterizes acheulean hand axes