Answer:
Wolly mammoths existed about five million years ago. Therefore, based on their half-life, the radioisotope which would be best suited to determine the age of a wooly mammoth bone is Uranium - 235 whose half-life is approximately 700 million years.
Explanation:
Uranium 235 is a variant or an isotope of Uranium. Isotopes are a derivative of a particular chemical element which are alike but different in the number of nucleons they contain.
In relation to age testing, the time taken for any specified property to decrease by half of its original value is called a half-life.
Thus the radioactivity of Uranium - 235 takes about 700 million years to fall to half it's original value.
Because of its half-life, Uranium - 235 is the best used when dating very old fossils.
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