87 rb has a half-life of 47 billion years, while 14 c has a life of 5,730 years. which isotope would you use to date a fossil from paleozoic era? briefly explain your choice

The isotope you would use to date a fossil from paleozioc era is the 47 billion years half-life 87rb as the paleozoic era dates from 540 to 248 million years ago.

Explanation:

Sometimes geologists need to estimate older fossils, like the ones from the paleozoic era which is the oldest of the three eras.

Carbon-14, the radioactive isotope of carbon used in carbon dating has a half-life of 5730 years, so it decays too fast and it is useful to date fossils younger than about 75,000 years.

To date most older fossils and to estimate how long ago rocks formed,  geologists use unstable radioactive isotopes of elements, decaying at constant, and this is called radiometric dating, rocksadiometric dating or radioisotope-dating of igneous rocks or ash located above, below or around the fossil vecinity.