21. The primary purpose of the passage is to
discuss the techniques of analyzing lead isotope composition
propose a way to determine the origin of the copper in certain artifacts
resolve a dispute concerning the analysis of copper ore
describe the deficiencies of a currently used method of chemical analysis of certain metals
offer an interpretation of the archaeological record of the Bronze Age
22. The author first mentions the addition of flux during smelting in order to
give a reason for the failure of elemental composition studies to determine ore sources
illustrate differences between various Bronze Age civilizations
show the need for using high smelting temperatures
illustrate the uniformity of lead isotope composition
explain the success of copper isotope composition analysis
23. The author suggests which of the following about a Bronze Age artifact containing high concentrations of cobalt or zinc?
It could not be reliably tested for its elemental composition.
It could not be reliably tested for its copper isotope composition.
It could not be reliably tested for its lead isotope composition.
It could have been manufactured from ore from any one of a variety of sources.
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