The organism show a free- living one that is anchored to the bottom of ponds and streams during the first part it is life cycle. what is the common name of a group to which  this organism belongs?  HELP PLZ ASAP 
A.Comb  jellies 
B. arthropods
C. cnidarians
D. echinoderms    
                                             
                                          
                                          
                                        
											 
			                   
					                  