Isotopes can be extinct.Logical formLearned from3 sentences. Exposure can be to radioactive isotopes.Logical formLearned from3 sentences. Isotopes may be produced within (earth materials).Logical formLearned from3 sentences. Isotopes may undergo an ingestion.Logical formLearned from3 sentences. An (isotope technetium-99m) can be metastable.Logical formLearned from3 sentences. A season may pertain-to isotopes.Logical formLearned from3 sentences. Research may focuse on a use of stable isotopes.Logical formLearned from3 sentences. Nuclei may pertain-to an isotope.Logical formLearned from3 sentences. Isotopes may undergo a distribution.Logical formLearned from3 sentences. (Isotope ratios) may be compared with compositions.Logical formLearned from3 sentences. Some isotopes can be constituted-of-or-filled-with lithium.Logical formLearned from3 sentences. An isotope can be constituted-of-or-filled-with sodium.Logical formLearned from3 sentences. An isotope can be preferred.Logical formLearned from3 sentences. (Sulfur isotopes) may undergo a fractionation.Logical formLearned from3 sentences. A radioactive isotope can be synthetic.Logical formLearned from3 sentences.