Final answer:
The statement is true. The relative refractory period follows the absolute refractory period, and only a stronger than usual triggering event can produce a second action potential during this time.
Step-by-step explanation:
True or false: Following the absolute refractory period is a relative refractory period, during which a second action potential can be produced only by a triggering event considerably stronger than usual. The statement is true. After the absolute refractory period, during which an action potential is impossible because the voltage-gated Na+ channels are inactivated, comes the relative refractory period. In this phase, the voltage-gated K+ channels are open and K+ is leaving the cell, making it harder, but not impossible, to depolarize the cell membrane again. To generate another action potential during this period, a stronger stimulus than the one that initiated the current action potential is necessary to overcome the outward flow of K+ and reach the threshold potential for an action potential.