natural
adjective nat·u·ral \ˈna-chə-rəl, ˈnach-rəl\
: existing in nature and not made or caused by people : coming from nature
: not having any extra substances or chemicals added : not containing anything artificial
: usual or expected
http://www.merriam-webster.com/dictionary/natural
nature
noun na·ture \ˈnā-chər\
: the physical world and everything in it (such as plants, animals, mountains, oceans, stars, etc.) that is not made by people
: the natural forces that control what happens in the world
: the way that a person or animal behaves : the character or personality of a person or animal
http://www.merriam-webster.com/dictionary/nature
