Final answer:
H. erectus/ergaster had a varied and omnivorous diet, increasingly incorporating meat, and adapted to cooking food, which supported anatomical changes including smaller teeth and jaws, and brain enlargement.
Step-by-step explanation:
H. erectus/ergaster was not tied to any particular dietary item; it had a varied and omnivorous diet. The fossil evidence suggests that this bipedal species had evolved to encompass a dietary strategy that included a higher consumption of meat and other high-quality, nutrient-dense foods. Increased use of fire and cooking techniques further contributed to changes in anatomy, such as a decrease in tooth size and jaw strength, necessary for processing raw, fibrous plant materials. These adaptations, along with others such as larger brain size, increased endurance, and the use of tools, allowed H. erectus/ergaster to thrive in a variety of environments and ultimately become a successful and long-surviving species.