Which pair of elements can be used to determine the age of a fossil that is over one billion years old? lead, which is radioactive, and uranium, which is stable carbon, which is radioactive, and nitrogen, which is stable argon, which is radioactive, and lead, which is stable potassium, which is radioactive, and argon, which is stable

Explanation:

There are some radioactive nuclides can be used to measure time on an archeological scale. One is the best example of this is radiocarbon dating. This process is based on the ratio of caebon-14 to carbon-12 in the atmosphere which is relatively constant.

The half time of C-14 5730 years  

Carbon-14 is a radioactive nucleus. It has a half-life of 5730 years.

All living tissues like plants and animal absorbed carbon-12 along with carbon-14 with same ratio of caebon-14 to carbon-12 in the atmosphere.

Carbon-14 dating is based on the ratio of carbon-14 to carbon-12 in the atmosphere which is relatively constant