It is a perfect example of a natural selection.
(I'm not sure if this is the exact answer that you are looking for.)
        
                    
             
        
        
        
The Vatican archives stores multiple precious documents and books of the world. These old documents dating hundred of years are kept in high nitrogen levels, in order to prevent the oxidation of the paper (papyrus). The presence of the high level of inert nitrogen in the air in the archives prevents any kind of damage that may caused to the paper or the ink on those documents. This high level of nitrogen, however, may affect the health of the individual by decreasing the oxygen levels in the body.
Hence, the answer is 'the oxygen level will be decreased in the body'.
 
        
             
        
        
        
 Answer:
b) Bioremediation
Explanation:
 The use of natural occuring or intentionally introduced micoorganisms to treat environmental pollutants is called as Bioremediation. 
- Most of the bioremediation processes includes oxidation-reduction reaction.
- The natural degradation process of pollutants is improved by bioremediation.
- Green plant, Decomposers and their enzymes are used in bioremediation to imrprove the condition of the environment.
 
        
             
        
        
        
Umm...
biology is the study of life 
is this the answer you're looking for?