Answer:
the vaccine causes the immune system to produce antibodies to the virus that causes the measles 
 
        
             
        
        
        
The correct answer is d. "Regeneration" means "forming new cells," and signifies that the disease-causing bacteria cells are multiplying. When there are more of these cells, there is a higher chance for antibiotic resistance (making it take longer for the antibiotics to work). Once there is a smaller concentration of these bacterial cells, the antibiotics become more effective. 
        
                    
             
        
        
        
Answer:
<h2> I don't know but my Answer is </h2><h3>from different environments ,each structure suits their environment better than the other's</h3>