Answer: Sex cell is the correct answer.
 
        
             
        
        
        
Your body constantly produces new cells. Normal cells follow a typical cycle: They grow, divide and die. Cancer cells, on the other hand, don't follow this cycle. Instead of dying, they multiply and continue to reproduce other abnormal cells.
 
        
                    
             
        
        
        
Your answer would be The microorganism was unicellular and had a well-defined nucleus.