Answer;
-NAD+ 
Explanation;
-When glucose breaks down into ATP, a large amount of the energy is stored as electron on special molecules (the electron carriers). When an empty electron carrier accepts a pair of electrons, it is reduced; when it gives those electrons up later on, it is oxidized. 
-NAD+ and FAD; also the two most common electron carriers in the body. NAD+ can accept a pair of electrons (and a hydrogen ion) to become NADH. 
 
        
                    
             
        
        
        
probably younger.----less sediment would mean less time.
 
        
             
        
        
        
<span>B is the correct answer
hope it helped</span>