Answer:
I believe that it would be copper because copper is all of those things.
Explanation:
 
        
             
        
        
        
Answer: 
                       Mass = 24.36 g of N₂
Explanation:
                    The balance chemical equation for the decomposition of NaNO₃ is as follow;
                                            2 NaN₃ → 2 Na + 3 N₂
Step 1: Find moles of N₂ as;
According to equation,
                  2 moles of NaNO₃ produces  =  3 moles of N₂
So,
               0.58 moles of NaNO₃ will produce  =  X moles of N₂
Solving for X,
                       X = 3 mol × 0.58 mol / 2 mol
                       X = 0.87 mol of N₂
Step 2: Calculate mass of N₂ as,
Mass = Moles × M.Mass
Mass = 0.87 mol × 28.01 g/mol
Mass = 24.36 g of N₂
 
        
             
        
        
        
It is supposed to protect the cell from it's surroundings, or from the outside.