That depends on the type of race you're talking about; nascar, dragcar, an Indy, off road, etc....... But for the most part, they all have one thing in commen, a high octane. Higher octane means, burns fast, better, and is better for you car. (the only racing car they might not use high octane fuel with might be off road racing, but I'm not sure)
A pit crew is a group of people there to fix a racers car when something goes wrong. They also fill the car up with gas, change tires and make adjustments during the race.
Nitrogen
Nitrogen, because it is an inert gas.
Most pro racing teams are using pure Nitrogen gas in their tires. This has the main advantage of minimising pressure changes as the tire warms up. It will also not feed a fire in a post crash fire.
No. A car will get better mileage with the correct tire pressure.
nitrogen
Nitrogen and oxygen = Air
a engine and if you have gas (and not a flat tire d;=D)
Nitrogen is used because it has less parts per million of water than compressed air. It gives a more predictable pressure increase over a given tire temp.
maybe the rubber in the tire expands more than the gas in the tire...but I don't really know.
A tire can effect your gas mileage by a lot. If you do not have a inflated tire you can get 2-3 mpg less than use usually get.
low gas, flat tire, broken gas