Answer:
Immune and Lymphatic Systems
Explanation:
 
        
             
        
        
        
DNA is a dynamic and adaptable molecule. As such, the nucleotide sequences found within it are subject to change as the result of a phenomenon called mutation. Depending on how a particular mutation modifies an organism's genetic makeup, it can prove harmless, helpful, or even hurtful.
Mutation (A)
 
        
             
        
        
        
Chemosynthesis, I believe. Bacteria at the bottom of the ocean use this process for food.