Rate of growth of a seedling over two weeks
        
             
        
        
        
Peristalsis<span> is a radically symmetrical </span><span> contraction and relaxation of muscles</span><span> that propagates in a wave</span><span> down a tube, in an anterograde direction.</span>
        
             
        
        
        
The answer is D - cellular respiration <span />
        
                    
             
        
        
        
<span>Allergy-
A medical condition that causes someone to become sick after eating, touching, or breathing something.
Allergen
A substance or object that causes allergies.
Hope this helps!!
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Acid rain, if I understand the question correctly.