C is correct. the rest is either about food webs or about both food webs and food chains. 
        
             
        
        
        
Answer:
You didn't give options to choose from so I'll just wing it.
Over-predation will most likely be the cause of the extinction of the butterflies
Explanation:
Since the birds are preying on them, their population will most likely go extinct because of the birds.
 
        
             
        
        
        
Answer:
Explanation:
 A mutation in DNA alters the mRNA, which in turn can alter the amino acid chain.
 
        
             
        
        
        
 Hypocalcemia or low calcium level is most usually the cause of electrolyte disturbance after a thyroid surgery.