Hello there!!
The answer, I think, would be A.
 UV radiation can create problems in the correctness of cell replication, which can result in mutated cells.
I hope this answers your question!
 
        
             
        
        
        
Explanation:
Magnesium Chloride : MgCl2
Sodium chloride : NaCl
Potassium nitrate : KNO3
Hydrogen oxide : H2O2.
hope this helps you.
 
        
             
        
        
        
Answer:
it regulates the amount of air or moisture leaving or entering the leave
Explanation:
this is because it has tiny pores which helps in regulating the moisture or heat content leaving or entering the leave
 
        
             
        
        
        
The carbon cycle. Although it's not specific, it talks about combustion or respiration. The reason I chose the carbon cycle, is because nitrogen DOES appear in photosynthesis, but you were strictly talking about carbohydrates. 
        
                    
             
        
        
        
metric system to be more clear