An index fossil represents a species that lived during A.
a long interval of Earth's history.
B.
Earth's entire history.
C.
a short interval of Earth's history.
D.
several intervals of Earth's history.
which one is it?

A5.000 g sample of niso4 h2o decomposed to give 2.755 g of anhydrous niso4. what is the formula of the hydrate? what is the full chemical name for the hydrate? what is the molar mass of the hydrate? niso4•_h2o what is the mass % of water in the hydrate?