Final answer:
Early humans had a diverse diet consisting of plant-based foods and cooked lean meat. Their food choices depended on the environment in which they lived.
Step-by-step explanation:
Early humans had a broad diet that included foods of different mechanical properties. Their typical diet consisted of a wide range of different foods of plant origin, including berries, fruits, nuts, roots, grains, and leaves. They also consumed a certain amount of cooked lean meat, which made up roughly 20% of their diet by weight. The meat had a low fat content and a high ratio of polyunsaturated to saturated fat. The choice of foods depended heavily on the environment in which people lived. In lush and warm environments, they had access to a variety of edible plants and animals, while in frigid and icier environments, they depended more on animals and fish.