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.
The softhearted Clay! From a not too popular but very good book series, Wings of Fire. I wish this series had as much of a fanbase as warrior cats once did, it deserves it. I drew Clay Mudwing from the Wings of Fire series. Still on the first book, but I adore all of the characters.