Likely a sterile medium means an uncontaminated culture (food free of living organisms) that will grow only the new bacteria introduced for analysis. Source(s): http://www.thefreedictionary.com/sterile
Stonepelt was Bluestar's first mentor and a very well-respected senior warrior of ThunderClan. It is revealed in this book that he took her to the Gathering on her second day as an apprentice because she had caught a squirrel very well for a new apprentice, and the squirrel had been as big as she was.
Proving them all wrong, Catanzaro proves that the next American Ninja Warrior can indeed be a 100-pound woman that can make mincemeat out of the fiercest of courses. Fans can see her and Steffensen in the traveling obstacle course which is visiting cities all across the United States.