Depends on the type of showing. Each breed association has it's own shows that are limited to that breed or sometimes crosses. Additionally, all different breeds or mixes can be used for performance-oriented showing. Indeed, many famous stadium jumpers or cutting horses were grade horses (no breed). It all depends what discipline you are in.
Arabian horses are a versatile breed and can compete and perform in any discipline that other horses can do.
The horses used are mainly draft types and draft type crosses.
Uh, if they didn't breed, how are they supposed to have more sea horses? Yes, sea horses breed.
Any breed of pig, including cross breeds are able to be used for showing.
A Stallion.
Some of the horses used in the US Cavalry were pretty much any horse breed they could get their hands on. FL Crackers, Paint horses, Quarter horses extc.
Black is a color and not a breed. Appaloosa horses can be black.
Buckskin is a color not a breed. There are buckskin Quarter Horses, Paints, ect. So the color of the horse has nothing to do with what they are used for.
All horses can cross breed with each other.
Showing, Racing, Breeding, and Pleasure Riding.
yes.
There are many mixed breed horses. Many people will breed 2 types of horses that are specialized in one area to get a horse that is even better at that one thing. There are many mixed breed horses where you cannot tell all the breeds in it. They call those horses "grade" horses.