One of the special characters of coelenterata only is the occurrence of (a) polymorphism (b) flame cells (c) hermaphroditism (d) nematocysts
Option D The cells characteristic of the coelenterates include stinging cells (cnidocytes or cnidoblasts or nematoblasts) for offence and defence. The stinging cells, when discharged, give out from a sac, the cnide or cnidocyst or nematocyst, a long threadtube that may coil around the prey, or attach to it, or inject a toxin, called hypnotoxin, into it to paralyse it.
