They get energy by preforming chemical reactions within the cell
        
                    
             
        
        
        
Answer: The different layers are a result of lighter parts (such as the continental crust) settling at the surface level and heavier parts (such as iron and nickel in the core) settling in the middle. The layers separate by density, otherwise known as compositional layering. The earth did not always have these layers, as it had to undergo cooling to form some of them (like the continental crust).
        
             
        
        
        
 the brain has to grow it happens because of the nervous system 
1.The heart is Beating 2. It is kicking
A baby is safe in the womb because it is well insulated and designed as the perfect baby carrier
        
             
        
        
        
It would be the vital capacity