Which of the following statements regarding the movement of substances across the plasma membrane is INCORRECT?
Correct: D
The Na+/K+ pump is crucial for maintaining both the resting membrane potential and the concentration gradients of Na+ and K+, which are vital for nerve impulse transmission and muscle contraction. While it contributes to osmotic balance, its primary physiological roles extend beyond just osmotic balance, encompassing the establishment of electrochemical gradients for nerve impulse generation and muscle contraction. The statement 'primarily to maintain osmotic balance' is an understatement and potentially misleading regarding its full physiological significance, especially in excitable cells where electrochemical gradient maintenance is paramount. All other options accurately describe their respective transport mechanisms.