The elaborate network of membranes in skeletal muscle cells that functions in calcium storage is the .

Sarcoplasmic reticulum

Explanation:

Sarcoplasmic reticulum is a membrane-enclosed sac-like structure present in the muscle especially the striated muscle or the skeletal muscles. The muscle reticulum morphological resembles the endoplasmic reticulum of the cell but since they are present in the sarcoplasm of the muscle, therefore, are referred to as sarcoplasmic reticulum.

The sarcoplasmic reticulum is not involved in the production of some molecule but it stores the calcium ions involved in the muscle contraction.

Thus, the Sarcoplasmic reticulum is the correct answer.

cells spend most of their time in interphase