The absolute age of a rock is the approximaye number of years ago that the rock formed. The absolute age of an igneous rock can be best determined by

Anstobacco uses;  

The us is first  the  u.s. economy  remains the  largest in the world  in terms of nominal  gdp. however, the  u.s. economy  loses its spot as the number one  economy  to china when  measured  in terms of  gdp  based on ppp. in these terms, china's  gdp  is $23.19 trillion exceeds the  u.s. gdp  of $19.42 trillion

Physical systems is the answer