What is the major characteristic of the relative refractory period?

The major characteristic of the relative refractory period is that a strong enough stimulus can depolarize the neuron and potentially trigger an action potential. During this phase, the nerve cell is undergoing a recovery process after an action potential has occurred. Although the cell membrane is returning to its resting potential, it has not fully reset. This means that while it is more challenging to initiate another action potential, it is still possible if the stimulus is sufficiently strong. This phenomenon is critical in understanding the timing and firing of neurons, as it highlights the importance of stimulus strength during different phases of the action potential cycle.

In contrast, the other choices describe states that do not accurately reflect what occurs during the relative refractory period. Specifically, during the absolute refractory period, no stimulus, regardless of strength, can elicit an action potential, indicating a complete unresponsiveness. The channels being fully reset aligns more with completion of the action potential cycle after the relative refractory period has ended. Thus, the correct choice emphasizes the possibility of depolarization with a stronger stimulus, which characterizes the unique conditions of the relative refractory period.