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a method of determining the age of an object by estimating the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope.
unstable isotopes that break down and give off energy in the form of charged particles (radiation)
the time required for half of a sample of a radioactive substance to disintigrate by radioactive decay or by natural processes
a classification kingdom made up of bacteria that live in extreme environments; differentiated from other prokaryotes by various important chemical differences
a member of the phylum Arthropoda, which includes invertebrate animals such as insects, crustaceans, and arachnids; characterized by having segmented bodies and paired appendages
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