Final answer:
In muscle mechanics, the Parallel Elastic Component (PEC) indeed contributes to resistance that must be overcome for muscle contraction. The concept that tetanus is caused by a stimulus to skeletal muscle faster than Ca removal from the Sarcoplasmic Reticulum (SR) is simplified; tetanus is more related to sustained Ca levels in the sarcoplasm.
Step-by-step explanation:
Statements a) and b) in your question relate to the properties of muscle contraction and the structural components involved in it. It is true that muscle contraction must overcome the passive elasticity in the Parallel Elastic Component (PEC) before movement occurs, as this elasticity provides resistance to stretch within the muscle. However, b) is partially inaccurate as the PEC also includes other elements beyond just the sarcomeres, such as connective tissue and extracellular matrix.
The sentence under c) seems to describe a scenario related to sustained contractions, which in reality refers to tetanus. When a skeletal muscle receives stimulation at a frequency higher than it can relax, it leads to a state of continuous contraction known as tetanus. However, stating that a stimulus to the skeletal muscle cell faster than the Ca in the Sarcoplasmic Reticulum (SR) can be moved causes tetanus is a simplification. In fact, in tetanus, the Ca is not reabsorbed into the SR quickly enough, leading to sustained high levels of calcium in the sarcoplasm, which results in sustained muscle contraction.
Therefore, while statement c) does relate to a real phenomenon occurring in muscle fibers, the specific details provided in the statement are not entirely accurate. For clarity, during tetanus, high intracellular Ca levels maintain the cross-bridge formation needed for contraction, as the sarcomeres continue to shorten without the relaxation phase occurring. Thus, statement c) could be considered a simplified explanation of tetanus but does not capture the full mechanism accurately.