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.
