Sodium channels in membrane can open in response to what?

why do sodium ions need channels in order to move into and out of cells?

what kind of channels are involved in establishinh rmp

Which of the following happens if the concentration of potassium in the extracellular fluid increases too much?A) Potassium would be taken up by the oligodendrocytes, so no net change in signaaaling would result. B) No signaling could occur. C) The Neuron would become hyperexcitable D) The sodium pumps would immediately fix the situation, so no net change in signaling would result.