I think that a) is chemical, and b) would be chemical
If Antarctica has coal beds, and coal is formed from pressured carbon, then it indicates that Antarctica once had living organisms. Because living things are carbon based.
Earth's age is best estimated by:
Answer: Out of all the options presented above the one that represents the best way to estimate the Earth’s age is answer choice D) using radioactive isotope pairs to date the oldest rocks. This method is best known as radiometric dating.
I hope it helps, Regards.
