Earth
The air animals and plants use to live is only the first level of the air around the Earth (the troposphere). The day to day changes in this level of air are called weather; the larger differences between distant places and from year to year are called the climate. Rain and storms come about because this part of the air gets colder as it goes up. Cold air becomes thicker and falls, and warm air becomes thinner and goes up. The turning Earth moves the air as well and air moves north and south because the middle of the Earth generally gets more power from the Sun and is warmer than the north and south points. Air over warm water evaporates but, because cold air is not able to take in as much water, it starts to make clouds and rain as it gets colder. The way water moves around in a circle like this is called the water cycle.