If I would have to make a good guess, I would choose A. 
        
                    
             
        
        
        
Answer:
sugar
Explanation:
The sides of the stepping stool are made of rotating sugar and phosphate particles. The sugar is deoxyribose. The rungs of the stepping stool are sets of 4 sorts of nitrogen bases. Two of the bases are purines-adenine and guanine.
 
        
             
        
        
        
Stars are formed in clouds of dust and gas (nebulae.) Nuclear reactions at the center (core) of stars gives enough energy to make them shine brightly for many, many years. The exact l<span>ifetime of a star depends on its size.</span>
        
                    
             
        
        
        
Answer:
D
Explanation:
Fermentation produces a net gain of 2 ATPs 
Aerobic respiration produces a net gain of 32 ATPs