To a geologist the most important use of index fossils is?

john adams was the 2nd president of the united states.

explanation:

i do not know if this question has options, but a main impact of the federal reserve act of 1913, which created the federal reserve bank, was the international use of the u.s. dollar, which soon became the world's leading currency - particularly during world war i, since many nations around the world asked the united states for money.

cultural achievements of the 1920's 2010  

1. cultural achievements and african american achievements in the 1920’s  

2. art and literature charles lindberg flew from ny to paris, france. became national hero; first transatlantic flight.  

3. greenwich village (new york) and the south side (chicago)  many artists, writers, and intellectuals flocked to these areas to share ideas  people lead bohemian, or artistic and unconventional, lifestyles