Answer:
A great example is the peppered moths evolution. Since the Industrial Revolution the birch trees started to turn black from the soot. This casued all the white moths to be eaten from birds. The ones that were left to mate were black moths which favored the black gene. So overtime black moths became more common. They were naturaly selected based on color to survived and pass down their black colored genes.  
Explanation:
 
        
             
        
        
        
 Well, it’s just because nucleotides do not contain an amino group. Nucleotides are composed of nitrogen base bonded to a sugar which is also bonded to a phosphate group. No amino groups in sight.
        
                    
             
        
        
        
During an emergency what you would usually want to do is a so-called threat and hazard analysis - C.
You would do this because you would want to observe and note which is a source of threat for you in a certain emergency situation. You would also to this to observe the possible hazards of doing a certain action/certain actions.