Final answer:
The Acheulean tools are characterized by a large number of bifacial elements, indicating refined craftsmanship and cognitive development in early hominins, such as Homo erectus.
Step-by-step explanation:
The type of tools that are characterized by a large proportion of bifacial elements is the Acheulean tool industry. Acheulean tools were far more sophisticated than the Oldowan variety and required improved cognitive abilities and motor skills to create. These tools were modified on both sides resulting in a symmetrical and efficient shape, often including hand axes, cleavers, and side scrapers.
Acheulean hand-axes, for instance, are formed into distinct shapes like cordate, ficron, and ovate, indicating a deliberate selection of raw materials with good flaking qualities. The biface tools, as they were worked on both sides, were predominantly used by Homo erectus from 1.6 million to about 200,000 years ago.
The soft hammer technique used in the creation of Acheulean tools allowed for more precise shaping and a sharper edge, enhancing the hominins' ability to hunt, process food, and manufacture simple clothing.