Answer:
Lipids
If i were to guess, without any answer choices, I would say that we get out energy from carbohydrates, and we store energy in lipids, so Lipids (being long chains) might have the most energy. 
Explanation:
Please tell me if this is wrong, I did not have much to work with without any answer choices, and this was very broad. :)
 
        
             
        
        
        
Answer:
ok we will were do I sign
 
        
                    
             
        
        
        
Answer:
mitochondria
Explanation:
Mitochondria is known as power house of a cell
 
        
                    
             
        
        
        
No, Darwin did not believe that they were different species. 
The differences in the finches proved his theory of evolution to be likely. The finches evolved based on traits that fit their environment. The different finches were the same species, however, their traits differed based on their environment.