this is not true.... a starfish can develope from 1cm of a cut off leg, some do this better than others, but they have the ability to do it....
silly marine biologists trying to save some corals on a reeceding reef went diving and caught all the predatory starfish they could, brought them on the boat and cut them all into many little pieces and threw them overboard to feed the fishies, when returning for starfish counting they couldnt figure how the starfish population skyrocketed when they caught almost all of them and "killed" them....lol some times the smartest people are so dumb....