Which radioactive isotope or isotopes would you use to date each of the following objects? explain each of your choices.
(a)-a 4 billion year old piece of granite.
(b)-a one million year old bed of volcanic ash that contains the footprints of hominids (human ancestors).
(c)-the fur of a woolly mammoth that was recently recovered frozen in a glacier.
(d)-a fossilized trilobite recovered from a bed of sandstone that is about 500 million years old.