For our B team, anyone can join, we had 35 or so people this year. We compete two different teams, 1st team, which contains everyone who will likely compete at states, and 2nd team, which is everyone else. They help each other, practice together, and everything. After invitationals, if someone from the 2nd team is looking better than someone on the first team, they get switched, events get moved around, stuff like that. So while the 1st team at the beginning of the year may look exactly like last year's state team, by the time state rolls around again, it could be(not likely, but...) completely different people, depending on who's shown they were the strongest in their events.
The C team is happy if it can find more than ten people interested...
2011 Events: Anatomy & Physiology, Disease Detectives, Ecology, Microbe Mission, Mission Possible, Optics, Birds, Protein Modeling, Technical Problem Solving
2012 Events: Anatomy & Physiology, Disease Detectives, Elastic Gliders, Trees, Microbe Mission, Protein Modeling, Remote Sensing