    [Sentence 1: Which group has young that, are born with  no tentaeles and alarge mouth?    ‘Sentence 2: The exceptions are the heroids, whose  young are miniature berolds with large mouths and no  tentacles, and the platyctenids, whose young live as  cydippid-Iike plankton until they reach near-adult size,  /but then sink to the bottom and rapidly metamorphose  into the adult form.