Signals can travel in either direction in both axons and dendrites A) pumping three positively-charged sodium ions out of the cell for every two positively-charged potassium ions they pump into the cell B) pumping both positivelycharged sodium ions and positively-charged potassium ions out of the cell C)pumping positively-charged sodium ions out of the cell and negatively charged chloride ions into the cell D)pumping positively-charged sodium ions out of the cell and negativelycharged potassium ions into the cell