The correct answer is option B, that is, diminished food supply.
Some of the animals move to comparatively short distances in search of food or more favorable breeding or living conditions. However, the majority of animals, which migrate do so in order to find more habitable conditions and food. The phenomenon can be witnessed in almost all the prime animal groups like mammals, birds, amphibians, fish, reptiles, crustaceans, and insects.
<span>A study of biology will help inform you about your lifestyle choices, because it will lead you to better understand the ways in which your choices about what you eat and how much you exercise actually affect the internal processes in your body and the drastic effect that you can have on them.</span>