C. The lungs can better exchange oxygen
        
             
        
        
        
Answer:
The answer is between a or b
but I strongly suggest the option a.
Evolution is the answer 
 
        
             
        
        
        
The answer is Echinoderms.
According to the Embryological studies, the most ancient chordates were closely related to the ancestors of the echinoderms. Echinoderms are members of the group Phylum Echinodermata of marine animals. Some known echinoderms are starfish, and sea cucumbers.
        
                    
             
        
        
        
Pro cells have cell wall but eukar don’t
        
                    
             
        
        
        
An open flame or burning flame