Large image view: Tracing marijuana to its roots
![[Photo: Read caption below]](/news/archives/news-archives-2002-2010/featured/07/marijuana/images/zoom/Wooller1.jpg)
UAF photo by Marmian Grimes
Matthew Wooller, director of the AV狼论坛 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.