malities and cancer are the leading causes of death among Contra Costa residents age 0-24 years. Infants, children and young adults have a very low risk of death and account for 3% of all deaths countywide. Between 2000 and 2002, there were 529 deaths among Contra Costa residents age 0-24 years. This means that there are approximately 175
The method of extraction of a metal from its ore depends on the metal's position in the reactivity series. Gold, because it is so unreactive, is found as the native metal and not as a compound [compound: A compound is a substance formed by the chemical union (involving bond formation) of two or more elements. ] .
Flint is a variety of microcrystalline or cryptocrystalline quartz. It occurs as nodules and concretionary masses and less frequently as a layered deposit. It breaks consistently with a conchoidal fracture and was one of the first materials used to make tools by early people.Novaculite  is another similar material. It has a sedimentary origin that is similar to flint but diagenesis and metamorphism have increased the size of the quartz microcrystals. It has been used for thousands of years for making sharp tools and weapons.