1. a wide variety of factors. heat, climate, weather, natural disasters that lower the population of prey animals, etc
2. well and example is this: it is getting hotter in Antarctica, causing the ice caps to melt. this change would make it harder for prey animals like penguins to find somewhere to live, thus making them easier food for predators. such as killer whales and polar bears.
3. the more trees we cut down to make room for buildings, for instance, causes many animals habitats to dissapear, the animals shortly after