There could be a lot of explanations for a horse shifting its weight off one of its front legs. It could be feeling pressure due to lameness, and trying to relieve that pressure. If the horse appears to be leaning back on its "heels" in both front feet and it already prone to hoof problems, it could have laminitis. It could of course just be resting a leg too but that is more common with the back legs. Mostly it's important to undestand your horse's habits--the biggest indicator of a problem is behavior abnormal.
Ironically, it's called "rear up" or "rearing up".
The back legs of a horse is called its hind legs.
A stand with three legs is a tripod.
Horses use all four legs.
in a way. the back legs support the horse and boost him off the ground to run. So yes. If the horse did not have back legs he would not be able to run.
No. A quadraped has four legs. A horse has SIX legs. Two legs in the back, and fore legs in the front.
They aren't designed to do it, if you'll take a horse and look at the way it walks, you'll see that it is reversed from us, to stand on their hind legs is like standing on our hands
their back legs
a bone in the thigh of the back legs of the horse.
That would be a tripod, which does indeed have three legs -- and is a stand.
tripod
A tripod
Yes they do kick back their legs like a horse does to protect themeselves.