Answer:
D.
Explanation:
It will stay the same no matter how the atoms are rearranged
 
        
                    
             
        
        
        
Answer:
A living organism's position in the flow of energy through an ecosystem.
 
        
             
        
        
        
Complex organisms need cells that can perform many different functions. they need to be supported on a cellular level. Without specialized cells you they won't be able to perform different functions. 
        
                    
             
        
        
        
The spinal cord is made up of bundles of nerve fibers.