Use the Diagram of an Action Potential to Answer the Following

Multiple Choice

Use the diagram of an action potential to answer the following questions.

-Phase 2, the plateau phase, of the action potential shown

A) is the result of $\mathrm{Ca}^{2+}$ flux out of the cell
B) increases in duration as heart rate increases
C) corresponds to the effective refractory period
D) is the result of approximately equal inward and outward currents
E) is the portion of the action potential when another action potential can most easily be elicited