Explanation:
In general, tumors occur when cells divide and grow excessively in the body. Normally, the body controls cell growth and division. New cells are created to replace older ones or to perform new functions.
 
        
                    
             
        
        
        
<span>settable solids, i hope this helps   </span>
        
             
        
        
        
Answer:
Gills allow for gas exchange
Explanation:
 
        
                    
             
        
        
        
C) Natural selection
When something happens in nature and something changes all of a sudden, the animals tend to adapt to what gives them more chances of survival.  As a result, a large amount of the population would attempt to adapt in a way that helps them survive.