<span>(According to Reference)
 
Whereas an onion epidermal cell has a cell wall, a human cheek cell does not. Instead, a semi-permeable membrane surrounds the cytoplasm of the cheek cell. While there are chloroplasts present in onion cells, they are absent in cheek cells.  </span>
        
             
        
        
        
Answer:
D)  Sea otters are a keystone species as they prevent a herbivorous species from completely destroying a plant species.
Explanation:
 
        
             
        
        
        
Proteins are diverse because of the various combinations of amino acids there are.
        
                    
             
        
        
        
Answer: A.
Explanation: The Earth has a magnetic sphere that protects it from the sun's particles. Even though the particles take a while to travel to Earth, whenever they are deflected that is what causes the Northern Lights.