Vertebrates and invertebrates

____________________ are ____________________ animals that have a spinal ____________________ . They are classified into five groups : mammals , ____________________ , ____________________ , reptiles and ____________________ . ____________________ are multicellular animals too but they don't have ____________________ column . They are classified into six gropus : molluscs , ____________________ , porifera , ____________________ , arthropods and ____________________ .