Why can't plants and animals live anywhere

Plants and animals can't live everywhere because they need resources that can be found in some biomes. For example a cactus can't live in the rain forest because they are not adapted to the climate and resources. 

Please be more descriptive, if this is on a school assignment then you most likely didnt include the full scentence. If this is exactly what your asking then animals can live in plenty of different places and different types adapt to different areas..