A team in standard academic competition format generally has four people, though one can play with fewer. There is also a lockout buzzer system involved. In some formats, one can recieve 15 points for an especially early buzz. It may be best to think of it as Team Jeopardy, expect that you don't have to wait until Alex finishes reading the question to ring in. Questions may cover just about anything, and their subject matter may not necessarily be associated with any academic field.
Invitational questions tend to lie somewhere between the two extreme formats.
NAQT, similarly, tries to strike a balance between the two extremes. It's important to know that new players almost never start out as superstars, and it is not unusual for even players with a fair level of experience to go through a round and be utterly stumped by most of the question material. Well, I could tell you that there was a simple way to establish definitively which team is best, but I'd be lying. Due to the different formats, each format has its own champion. Think of it like pro tennis, which different players or teams being best on different surfaces.