Final answer:
The use of fire to frighten animals and increase hunting productivity was a major change in human existence. It was crucial for survival and development, representing a significant evolutionary and cultural advancement.
Step-by-step explanation:
The major change in human existence that resulted from the use of fire which is most foundational and impactful is d) the ability to frighten animals and increase hunting productivity. The use of fire by early humans had profound effects, including improved tool-making and cooking, but its role in enhancing hunting capabilities was transformative. Controlled fire allowed for the successful hunting of animals by warding off predators, which increased survival rates and contributed to the growth and development of human communities.
Controlled fires also aided in cooking meat, which not only made it easier to consume and digest but also facilitated dietary changes that were consequential for human evolution. More broadly, the regular use of fire and the technological advancements it enabled characterized a significant step in the evolution of human culture and the development of agriculture.