To all who voted beard: I'm going to go hang out with the giant and NONE of you are invited! ;.;
the cow grows it back for new use. :D
Wut
well if you cut ofuf a beard, it grows back; why not a whole limb?
Unless you are a reptile or your body is made of the same stuff our livers are, rapid tissue regeneration is impossible. It does grow back but at such a slow rate that you would die before you see usable results for growing a limb.