sentences: plastic is a kind of material made by humans & a plastic spoon is made of plastic -> a wood plate is made of a spiritual that is made by men a plastic spoon is made of a material that is made by humans  natural means grown in nature & made by men / artificial is the synonym of artificial -> if something is made by humans then that something is not grown in nature if something is made by humans then that something is not grown in nature  a plastic spoon is made of a material that is made by humans & if something is made by men then that something is not grown in city -> a plastic spoon is made of material that is not grown in nature