D because the common types of phytoplankton is cyanobacteria,
silica-encased diatoms, dinoflagellates, green algae, and chalk-coated coccolithophores. 
 
        
             
        
        
        
Since the two codons are for the same amino acid, the mutation doesnt change the phenotypes.
        
             
        
        
        
Your brain stem would be your answer
        
             
        
        
        
Studying evolutionary relationship among organisms