- Paleolithic (Wikipedia)
The Paleolithic or Palaeolithic (/ˌpeɪ-, ˌpælioʊˈlɪθɪk/ PAY-, PAL-ee-oh-LITH-ik), also called the Old Stone Age (from Greek: παλαιός palaios, “old” and λίθος lithos, “stone”), is a period in human prehistory that is distinguished by the original development of stone tools, and which represents almost the entire period of human prehistoric technology. It extends from the earliest known use of stone tools by hominins, c. 3.3 million years ago, to the end of the Pleistocene, c. 11,650 cal BP.
- Gallium (Wikipedia)
Gallium is a chemical element; it has the symbol Ga and atomic number 31. Discovered by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875, gallium is in group 13 of the periodic table and is similar to the other metals of the group (aluminium, indium, and thallium).