Because we have smelled them so long we are used to them
        
             
        
        
        
Cells at Work (Hataraku Saibou)
        
             
        
        
        
Answer:
cutting down all trees for lumber
 
        
             
        
        
        
I believe the answer is linear :)
 
        
             
        
        
        
The worm feeds via a "pumping" action in which it first uptakes the fluid surrounding it. Then, it expels the fluid while trapping any bacteria within it. The bacteria are then digested for energy and nutrients.