Large image view: Tracing marijuana to its roots
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ÃÛèÖÊÓƵ photo by Marmian Grimes
Matthew Wooller, director of the ÃÛèÖÊÓƵ Stable Isotope Facility, holds a jar of calibration standards in the facility's weighing room. The facility uses benzoic acid as a calibration standard for its instruments.