Question

Archaeologists use the half-life of ___________ to date organic materials.

A. uranium-238
B. carbon-14
C. carbon-12
D. uranium-235

Answer 1

It needs to be radioactive. That eliminates one of them.

For an archeologist, you would need a REALLY LONG half-life - more than just a few thousand years. That eliminates another one.

Kind of a toss-up between the last two.

Answer 2

1) Archaeologists are typically not paleontologists and don't deal with fossils
2) Organic material is based on carbon.
3) carbon 12 is stable.
4) carbon 14 has a 1/2 life of 5700 years

so the answer is...