Definition of ETHNOMEDICINE. : the comparative study of how different cultures view disease and how they treat or prevent it; also: the medical beliefs and practices of indigenous cultures.
Ten materials familiar to various prehistoric cultures are now known to be chemical elements: Carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin, and zinc. Three additional materials now accepted as elements, arsenic, antimony, and bismuth, were recognized as distinct substances prior to 1500 AD.
An element is a substance consisting of atoms which all have the same number of protons - i.e. the same atomic number. Elements are chemically the simplest substances and hence cannot be broken down using chemical methods. Elements can only be changed into other elements using nuclear methods. Although an elementâs atoms must all have the same number of protons, they can have different numbers of neutrons and hence different masses. When atoms of the same element have different numbers of neutrons, they are called isotopes. The Most Abundant Elements