[Ar] 4s1 is the correct answer 
 
        
             
        
        
        
Answer:
what?
Explanation:
i dint get it is there a joke or somthing
 
        
             
        
        
        
Answer:
Regulated gene expression is crucial to the proper growth & survival of an organism and cannot be over-emphasized. Without it, the genetic code of a chromosome is the equivalent of a computer data file without the appropriate application to run it.
 
        
             
        
        
        
The answer is nucleotides