If you heat water to exactly one hundred degrees Celsius at sea level, it boils immediately and turns into steam. A polar bear's fur loses heat efficiently when the temperature drops below minus twenty degrees Celsius in the Arctic. When animals migrate south for the winter, ecosystems remain balanced and biodiversity is maintained. If forests disappear due to deforestation, countless species lose their natural habitat and face extinction. Scientific facts and natural laws all work according to this principle: for every cause, there is always a predictable effect.