Accordingly, by observing how much of a radioactive substance has decayed, scientists are able to determine how old that substance is.

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The FBI has the lead in that investigation, of course, and has said in its statement that they will be conducting further tests to determine what the nature of the substance is.

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"Additional documentation indicates he refused to submit to a chemical analysis to determine alcohol concentration or presence of an impairing substance at the time of the citation, " the company said.

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