Answer:
The sodium-potassium pump is an active transporter because it needs to move sodium and potassium ions against the concentration gradient.
Explanation:
You have to think of it as outside vs inside the cell.
Outside the cell, you have 5mM K and 150mM Na. Inside the cell, you have 100mM K and 10mM sodium. Without the transporter then the ions would go from greater concentration to lower concentration.  Energy keeps the ions going from the way they would naturally happen.
 
        
             
        
        
        
The elephants skull, I believe.
        
                    
             
        
        
        
The vascular cambium is a plant tissue located between the xylem and the phloem in the stem and root of a vascular plant. Its functions is for secondary growth. It makes new phloem towards the outside of the plant and new xylem towards the inside. Good luck!
        
             
        
        
        
Answer: Foods with calcium
The amount of bone tissue in the skeleton or bone mass can keep growing until the age of  30. It is recommended to eat food with calcium prior to this age for maximum strength and density of the bones. Examples of food rich in calcium are dairy foods, green leafy vegetables, beans, nuts, fish and a lot more.