Final answer:
Homo ergaster's eyes indicated evolutionary changes, and Homo erectus made stone tools as part of the Acheulean industry. They were one of the first hominids to harness fire roughly 1.7-2.0 million years ago, which allowed them to cook, stay warm, and potentially protect themselves.
Step-by-step explanation:
The importance of Homo ergaster's eyes lies in the unique structure of their skulls, which had an uninterrupted bar of bone above the eyes, indicating evolutionary changes from their predecessors. Regarding tool-making, Homo erectus learned to make tools from stone. These tools, part of the Acheulean industry, were more complex and sophisticated compared to the earlier Oldowan tool industry. They included hand axes and cleavers, which were found throughout Africa, Europe, and the Middle East, dating from approximately 1.6 million years ago (MYA) to 200,000 years ago.
There is evidence that suggests that Homo erectus was using fire around 1.7-2.0 MYA, making it one of the first hominids to harness this capability. This 'discovery' of fire allowed Homo erectus to cook food, provide warmth, and possibly ward off predators, changing their way of life dramatically. Fire was a crucial factor in the successful spread of Homo erectus out of Africa and into Europe and Asia.