Answer:
Stabilizing selection
Explanation:
Stabilizing selection is the most common form of natural selection that is not easy to notice in a population as the change is less drastic.  It occurs when average or intermediate phenotypes of a trait in a population are favored, while the extreme phenotypes of that trait are not favored by the forces of natural selection. Over time, intermediate or non-extreme traits become more common in the population, while extreme traits become less common.
 
        
             
        
        
        
Enzymes are sometimes called biological catalysts 
        
             
        
        
        
The natural selection process applies majorly inside back species wether than between species.