Based on the information provided, the correct answer to the given question is (e) None of the above is correct.
Let's discuss why the other options (a) through (d) are not correct:
(a) Skeletal muscle contraction does not equal the duration of the action potential. The action potential is a brief electrical event on the cell membrane, which triggers the contraction. However, the duration of the muscle contraction is generally longer than the action potential itself because the contraction-relaxation cycle of the muscle fibers lasts beyond the action potential.
(b) Skeletal muscle contraction does not equal the duration of the absolute refractory period. The absolute refractory period is the time during which a second action potential cannot be initiated, no matter how strong a stimulus is applied. Muscle contraction duration is influenced by the availability of calcium ions and ATP, and can last beyond the refractory period.
(c) Skeletal muscle contraction does not precede the refractory period. The contraction is initiated by the action potential, and thus follows the initiation of the action potential, not precedes it.
(d) Skeletal muscle contraction does not end immediately after the refractory period is over. The contraction cycle, including the sliding filament mechanism, continues until calcium ions are actively reabsorbed into the sarcoplasmic reticulum, and the muscle fibers relax. This process is not directly correlated with the end of the refractory period of an action potential.
Therefore, the only suitable answer in this case is (e) None of the above is correct, indicating that the choices provided do not accurately describe the relationship between skeletal muscle contractions and action potentials or refractory periods.
