Question

carbon-14 is the typical radioisotope used to date materials; however, it has a limitation to 40,000 years. a scientist who wants to date materials older than 40,000 years would most likely use which radioisotope?
uranium-238
rubidium-91
lodine-131
cobalt-60

Explanation:

Uranium - 238 has a very long half - life and is used for dating very old materials. Rubidium - 91, Iodine - 131, and Cobalt - 60 are not typically used for dating ancient materials.

Answer:

uranium - 238