Who long dose it take for a starfish to grow its amr back?

A starfish can regrow an entire new arm in about a month. The process begins with the formation of a small bud at the tip of the stump. The bud then grows and develops into a new arm, complete with all of the necessary structures, such as skin, muscles, and nerves. The starfish can also regenerate other body parts, such as its stomach and intestines.