Where air pollution is not especially severe, predators have much more impact on leaf-beetle populations than parasites do
        
             
        
        
        
Cell wall.
Made of cellulose and acts as a stronger cell membrane in a plant cell
        
                    
             
        
        
        
Explanation:
is this an actual question!?? lol!
 
        
                    
             
        
        
        
In small intestine millions of micro villi are present for greater absorbption of digested food.
        
             
        
        
        
Answer:
Active uptake (which I think you mean active transport) is important when the concentration gradient is against that of a certain substance, so it doesn't cross the membrane through diffusion or passive transport. It is sometimes necessary if a substance needs to move across a membrane but can't do so due to electrical charge or that there is a substance on the other side of the membrane preventing diffusion.
Explanation: