Final answer:
The amount of tension a muscle fiber can produce is influenced by sarcomere length, motor unit recruitment, and calcium concentration, all of which are crucial for optimal muscle contraction and force generation.
Step-by-step explanation:
Factors Contributing to Muscle Tension in Muscle Fibers
The amount of tension produced in an individual muscle fiber is influenced by a variety of factors. These factors include sarcomere length, motor unit recruitment, and calcium concentration. Each plays a significant role in the muscle's ability to generate force.
Therefore, the correct answer to the factors contributing to the amount of tension produced in an individual muscle fiber is: d. All of the above.