Derived from a single fertilized ovum or embryonic cell mass.
                                                            
                                                     
                        
                                                
                        
                        
                            Means single. In monozygotic twins one fertilized egg seperates into two identical zygotes.
                                                            
                                                     
                        
                                                
                        
                        
                            derived from a single fertilized egg; "monozygotic twins" 
                                                            
                                                     
                        
                                                
                        
                        
                            Identical twins, born after a single early embryo splits into two, producing genetically identical fetuses.
                                                            
                                                     
                        
                                                
                        
                        
                            formed from a single fertilised egg.
                                                            
                                                     
                        
                                                
                        
                        
                            identical; one egg is fertilized by one sperm and then splits