It depends on how big the horse/pony is but, really if it's your horse,you should know!!
no, only if you want to rub the horse down. you have to use a proper horse brush
It's a brush you hold in your hand to use.
for what purpose would you use a body brush on a horse
That would be a curry comb. You use the brush like this, in case you don't know: Make firm circular motions on the horse's coat. Then, when the dirt/mud/whatever is loosened, use the dandy brush (aka stiff brush) to brush the stuff of. You use that brush with a flick of the wrist.
you use a hoof pick
yes you can as long as you clean all the hair and dirt from it doing so is safe
For a horse with a short mane (pulled) you can rake through it with the human brush [unless it's really thin because raking breaks the hair so it will, not dramatically, but it will thin] For a horse with a long mane you can not use a human brush and you NEVER use it on a tail ESPECIALY when showing. Even more so in Arabs and dressage.
A steady brush hand comes from practice and building up the needed muscles for holding the brush at the appropriate level.
A body brushand a plastic curry comb for stubborn mud.
It is best if a hard or Dandy brush is not used on the face or lower legs as it can be too rough for these sensitive areas.
Well a horse brush is the best thing to have, but if you currently do not have one then a nice scrubby wash cloth will work OK.
leg and body if you have a horse that lives in a filed you can use it on body insted of a body brush