Which of the following is a characteristic of muscle fibers that adhere to the All-or-None Law?

Muscle fibers adhere to the All-or-None Law, which means that they respond to stimulation in a binary manner: they either contract fully or not at all. This principle applies to individual muscle fibers, indicating that when a fiber is stimulated above a certain threshold, it will generate a complete contraction; otherwise, it remains relaxed. This characteristic is fundamental to understanding how muscle fibers function at a cellular level, ensuring that every contraction is a maximal response to stimulation, thus allowing muscles to perform their functions efficiently and reliably.

The other choices do not reflect the nature of the All-or-None Law. Partial contractions are not possible for individual fibers under this law, and while the fibers do relax when stimulation ceases, this does not define their contraction behavior in response to stimulation. Additionally, differentiation based on stimulus strength pertains more to the graded responses of entire muscles, rather than to the contraction characteristics of individual muscle fibers governed by the All-or-None principle.