Answer: Excretory
Explanation: My grandpa went through this recently and I had to learn all about it. :(
 
        
                    
             
        
        
        
Answer: B
Explanation:
They inject their DNA into the cell, which reprograms that cell to become that virus. This is why viruses are so deadly and can spread throughout the body and to others easily, and efficiently. 
 
        
             
        
        
        
The breakdown of tertiary and quartinary structures in a protein, a change in the active site
        
             
        
        
        
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It's A, because it's always important to drink water. If you think about it, all the other answers seem invalid.