Final answer:
The period of total depolarization of the neuron membrane when the neuron cannot respond to a second stimulus is called the absolute refractory period. During this period, another action potential cannot be generated because the voltage-gated Na+ channel is inactivated. A new action potential could be started only by a stronger stimulus than the one that initiated the current action potential.
Step-by-step explanation:
The period of total depolarization of the neuron membrane when the neuron cannot respond to a second stimulus is called the absolute refractory period.
During the absolute refractory period, another action potential cannot be generated because the voltage-gated Na+ channel is inactivated.
Once the voltage-gated Na+ channel returns to its resting state, a new action potential could be started, but only by a stronger stimulus than the one that initiated the current action potential.