Of course they can. A team in any game must continue playing even if every quarterback is injured. Many teams don't even dress a third quarterback in games. For example I know the Denver Broncos didn't even bring a third quarterback to the super bowls they played in the late 90's. If both quarterbacks got injured in the game wide receiver Rod Smith would have come in at the quarterback position.
None
No
The quarterbacks for the 1975 Super Bowl IX were Pittsburgh Steelers Terry Bradshaw, and Minnesota Vikings Fran Tarkenton.
Click on the 'Super Bowl Starting QBs' link on this page to see the quarterbacks who started for their team in the Super Bowl.
Doug Williams
favre and elway
It has never happened in the same Super Bowl game.
Were the starting quarterbacks in superbowl 1; Nameth & Unitis
Super Bowl XXX - Neil O'DonnellSuper Bowl XLV - Ben Roethlisberger
Super Bowl XXX - Neil O'DonnellSuper Bowl XLV - Ben Roethlisberger
Favre was the backup for that season behind Don Majkowski who was injured that same season. Favre was brought in and became the starter from that point on.
Super Bowl XVI: Ken Anderson Super Bowl XXIII: Boomer Esiason