Answer:
Sarcoplasmic reticulum.`
Step-by-step explanation:
Muscle fibers are formed by the process of myogenesis in humans. These fibers help in the contraction of the muscle and also helps in the body movement.
Sarcoplasmic reticulum is a cell organelle present in the muscle fibers that corresponds to the structure of endoplamsic reticulum. Sarcoplasmic reticulum stores the calcium ions in the muscle fibers.
Thus, the answer is sarcoplasmic reticulum.