We live on a unique planet named Earth - the only place we know of that has air and water and is able to support life.
Earth supports many forms of life - on land, in the waters, and in the air.
Our air and oceans were formed from gases that seeped from the Earth as it cooled after formation. The Earth has a solid core made up mainly of iron and nickel. When the Earth had just formed, over 4 billion years ago, radioactive material in its interior was generating a great deal of heat. The heat couldn't dissipate quickly enough and the interior grew hotter and hotter. After another billion years or so the interior had become so hot that the iron melted and sank to the centre, forming the core.