The answer would be the second option. The best reason for doing more background research after making an observation and before forming a hypothesis is to prevent making the same mistakes made in a prior experiment. It is to make sure that you are able to see the problems of a research and make an experimental design that will minimize the errors.
        
                    
             
        
        
        
DNA replicates before cell division, duplicating chromosomes. This occurs during S stage of interphase! Now each chromosome has two identical double helical models.
        
             
        
        
        
C, decrease.
If the trait is easy to be seen by predators, they will be caught more often than those without the trait, thus reducing the frequency of the trait.
        
             
        
        
        
Answer:
The answer is option C : a bacterium