One important phenomenon shown by coelentrates Share with your friends Share 1 Summaiyya Khan answered this Coelenterates show polymorphism, that is, occurrence of more than one type of individual in a population. The most common forms are- Polyp and medusa. 0 View Full Answer Joy answered this they have stinging cells which secret hypnotoxin which paralyses the prey and in found fatal for the swimmers. 0