The simplest form of matter which cannot be further simplified called element. Suppose, we know that, Iron is an element do something weird with it, to change it’s simplest form of matter state. i.e. burn the iron, you know that it will not change because it is also an element. We can change wood’s matter state because it is a matter and the element is defined as “a simplest form of matter is called element, if we change wood’s matter state by burning it then it becomes coil means “carbon” which is an element. Hence it proved that The simplest form of matter is called element.