Final answer:
The Acheulean tool tradition involved crafting cutting edges by carefully chipping away flakes from tennis ball-sized rocks, resulting in teardrop-shaped, symmetrical bifacial hand-axes.
Step-by-step explanation:
The style of stone-tool making that involves knocking a few flakes off tennis ball-sized rocks to produce cutting edges is known as the Acheulean tool tradition. Acheulean hand-axes are distinctive for their teardrop shape and symmetrical bifacial design, a significant evolution from the earlier, simpler Oldowan tools. Made by carefully chipping away flakes from the stone core, Acheulean tools were not only used as hand-axes but also for cutting, scraping, and chopping tasks, which represented a leap in human engineering and cognitive abilities.