i think only thoroughbreds can. but maybe others.
Typically races are restriced to certian breeds, but some will allow other breeds to participate, like an annual race meeting of Thoroughbreds versus Quarter Horses and the like.
women were discriminated by not being able to watch or participate. But the only event the women were able to participate was in the chariot races, only if they owned the horses.
Large races like the Kentucky Derby allows 20 horses. The average number for smaller races is 8 to 10 horses.
If there are alien races they indeed might have multiple ears.
NO, people also like to race Quarter horse, Mules, Arabs and other breeds. No, most common race horses are thoroughbreds, but Quarter horses have also been known to do well. (There are many other breeds that race to.)
No one can know for sure if alien races have multiple eyes, but it is possible.
Yes. Some alien races have multiple heads. But currently, it is unknown.
Yes. Some alien races have multiple hearts. But currently, it is unknown.
Yes. Some alien races have multiple legs. But currently, it is unknown.
Yes. Some alien races have multiple fingers and/or toes. But currently, it is unknown.
A half-breed is someone with parents of two different races.
Multiple nostrils would allow alien races to breathe better, so it is possible.
There is no way to know if any alien races have multiple breasts. There is no proof that alien life exists.