North Carolina Tar Heels in 1957
The San Francisco Dons in 1956. They went 29-0.
Nobody
Theoretically yes although it is extremely unlikely
WWE Champion, World Heavyweight Champion, World Tag Team Champion, WCW Tag Team Champion, Hardcore Champion, undefeated at WrestleMania (15-0)
No, Ronda is undefeated in MMA, having won 12 fights (3 by knockouts and 9 by armbar submission). She is the first and current UFC Women's Bantamweight Champion.
6 rounds this is how it works round 1 32 undefeated 2 16 undefeated 3 8 undefeated 4 4 5 2 6 1
Bill Goldberg, the professional wrestler, is two time champion in the WWE and enjoyed his reputation as undefeated champion. He is now retired and has become a TV Presenter on the DIY Channel.
Dennis Hogan, and Irishman, is now the middle weight boxing champion of Australia. He beat Nathan "King" Carrol for the title. He is undefeated after 16 bouts.
USC
Rocky Marciano, who retired undefeated with a record of 49 wins against zero losses.
Many of the champions in UFC have been able to defend their titles multiple times and each can stake a claim to be one of the top or undefeated champion of all time. Some of the top guys include: a. Anderson Silva - 10 title defenses b. Georges St-Pierre - 8 title defenses c. Jose Aldo - 6 title defenses d. Jon Jones - 5 title defenses All these 4 champions can potentially retire as an undefeated champion but personally I feel Anderson Silva is the best pound for pound fighter in the world and has the greatest chance of being an undefeated champion.