In the Process of Continuous Propagation,all of the Following Are

Multiple Choice

In the process of continuous propagation,all of the following are true except

A) the action potential is triggered by graded depolarization of the initial segment.
B) at threshold,sodium channels begin to open rapidly.
C) local currents depolarize the region just adjacent to the active zone.
D) depolarization of the axonal membrane only occurs at nodes.
E) each step takes about one millisecond.