The diagram shows the transport of ions across the cell surface membrane. Inside is a low concentration of sodium ions (Na+) and a high concentration of potassium Outside the cell there is a low concentration of K⁺ and a high concentration of Na*. [Figure 13.1 showing a cell membrane with carrier molecule and ion movements] The carrier molecule is a pump which exchanges Na* for K+ ions. Which ionic movements are represented by the arrows? active transport of K+ active transport of Nat diffusion of Nat diffusion of K+

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