What is the role of myelin in neurons? a. to change the direction that na+ and k+ move through ion channels during the action potential. b. to increase the speed that action potentials travel down the neuron. c. to prevent the neuron from generating action potentials. d. to cause multiple sclerosis when present and intact, as it blocks action potential movement and must be removed by the immune system.

The correct answer is option C, electric current

Electric current is due to the flow of electrons. In this case the two metal rods act as electrodes with in a conducting liquid. A chemical reaction takes place at the electrodes due to which free electrons are released. These electrons starts traveling from the region of high negative potential to the regions high positive potential through the connector connecting the two electrodes thereby producing electric current.