A、To show some men depend on a particular food. B、To show the diet of some people is still primitive. C、To show different people

One of the reasons for our success as a species is our ability to eat and thrive on a large variety of foods. Many animal species have become extinct or are on the verge of extinction partly because they lack this adaptability. They need to feed on particular food plant or a particular kind of animal or insect. If this source of food is for any reason removed then the animal concerned is unable to change to a different diet. Gradually it becomes extinct. But human beings are almost entirely free from the limitation of any particular food requirements. We are able to survive on a wide variety of foods both animal and vegetable. For example, the Eskimos are almost totally meat eaters: seal, bear, whale meat and fish form their whole diet; the Aborigines of Australia, living in desert regions, have leant to survive by making use of different insects as food to supplement their diet of wild fruits and roots.