It is called Commensalism. 
The shark is neither harmed or benefited but the remoras get the benefit of this relationship without harming the shark.
        
             
        
        
        
The mutagens that result in cancer damage DNA by (b) weakening the DNA strand or interfering with base pairing. This mutagens are called carcinogens, if they cause a damage to <span>a gene that makes a </span>DNA<span> repair protein, it means that a cell will have less ability to repair itself, and ,as a result, this will lead to formation of cancer.</span>
        
                    
             
        
        
        
Neither is correct actually
        
                    
             
        
        
        
Answer: Bacteria gain resistance to drugs because of mutations (permanent and random changes to their DNA) which means they have changed DNA coding, giving them the ability to resist the drug fighting them off. As a result, they survive and reproduce. Over time, more and more bacteria are generated as the DNA code for resistance is passed on over generations. This results in bacteria having the ability to resist drugs. This is particularly prevalent with antibiotics.
 
        
             
        
        
        
Answer:
an Abiotic Factor
Explanation:
The non-living components of the environment are known as abiotic factors. Abiotic factors include things such as rocks,water,soil,light,rocks etc...