D.)The enzyme changes shape and no longer fits the substrate.
High temp causes enzymes to speed up the reaction but too much heat and the enzyme might denature, losing its shape. 
 
        
             
        
        
        
A I thin because it will grow faster because its temperature is normal unlike B
 
        
             
        
        
        
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Catalyst speeds up the reaction rate of a chemical reaction
        
                    
             
        
        
        
The answer is (a.) taproots can store a lot of food, while fibrous roots do not.