Because they have been genetically selected to race. Their body structure (long legs, lean body, "hot" or high-strung temperament) enables them to run faster than other horse breeds.
No, I think Kentucky is more known for Kentucky blue grass and thoroughbred race horses (Kentucky Derby).
Thoroughbred
No, only Three Year Old Thoroughbred race horses registered in the Jockey Club of America are eligible to run in the Kentucky Derby.
The Kentucky Derby is a Grade I stakes race for three-year-old Thoroughbred horses, held annually in Louisville, Kentucky, United States on the first Saturday in May, capping the two-week-long Kentucky Derby Festival.
Twenty horses can race at a time
The Kentucky Derby is a horse race, you would win it on a horse, specifically a three year old Thoroughbred.
Equus caballus. The breed is the Thoroughbred.
the best racehorse in the usa is the thoroughbred
Actually, almost every horse race is limited specifically to Thoroughbred horses. While Arabians, Quarter Horses, Paints, and Appaloosas also race, the major races - the Kentucky Derby, Preakness Stakes, Belmont Stakes, and Breeders' Cup - are limited to Thoroughbreds only.
The ancestry of the modern thoroughbred traces back to three main sires. The Darley Arabian, the Godolphin Arabian, and the Byerly Turk.
There is not an official record of how many Kentucky Derby horses have been injured in the race. This is also because injuries may have been caused by the race but appeared later.
I don't think color matters but you generally don't' find paint thoroughbreds.