When potassium diffuses through the cell membrane, in which direction does it mostly flow?

Potassium ions typically have a higher concentration inside the cells compared to the extracellular space. As a result, when potassium diffuses through the cell membrane, it generally moves from the intracellular space to the extracellular space due to the concentration gradient. This movement is facilitated by potassium channels in the membrane, which allow potassium ions to flow out of the cell.

The tendency of potassium to flow outwards is important for maintaining the resting membrane potential of the cell and for the function of various cellular processes, such as muscle contraction and neuronal signaling. The process is influenced by the electrochemical gradient, which drives potassium ions to move out of the cell where they are in lower concentration.

Thus, the movement described in the correct answer aligns with the known behavior of potassium ions during diffusion, making it the appropriate choice.