C. 
Every change in a species is coded within the DNA. But the bird had lost a toe an accident. So the toe-loosing-option isn't true because not every bird looses his toe.
(Example: If a women gets bitten by a snake on the arm and gets the arm removed from her body and then in a year or so has a baby with her new husband. The baby won't be born with one arm because his/her mother lost her arm.) <span />
        
             
        
        
        
By looking at them with the microscope and analyzing it and then use the zoom and zoom it in more to get a better view of the molecules
        
                    
             
        
        
        
Answer:
Gravity?
Explanation:
These are the things needed for life: water, air, food, light, shelter, and space. It doesn't include gravity.
 
        
                    
             
        
        
        
Answer:
Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport, and sensing. Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane