Answer: This is an example of organizational heirarchy. 
Explanation: These biological structures are designed in a way that the whole system consist of different parts serving its own unique purpose, making up a full functional system. It goes from; atoms, molecules,cells, tissues and organs which makes up a system. Digestive system for example is composed of atoms, molecules,cells, tissues and organs that helps to digest amd convert food into energy(ATP).
 
        
             
        
        
        
The plants might die out because there is no one to pollinate them
        
             
        
        
        
Answer:
In water or acids, the metals trade places with hydrogen. The hydrogen escapes as a gas, and metal atoms, no longer attached to the object from which they came, dissolve in solution.
sorry if I'm wrong but I wrote this in my hw and it was right so ye
 
        
                    
             
        
        
        
The body needs calcium and phosphorous because phosphorus works with calcium to help build bones