what are the five characteristics of cnidarians?
['Radially Symmetrical.', 'Body multicellular, few tissues, some organelles.', 'Body contains an internal cavity and a mouth.', 'Two different forms exist, medusa and polyp.', 'Reproduction is asexual or sexual.', 'Has a simple net like nervous system.', 'Has a distinct larval stage which is planktonic.']