What structure in skeletal muscle cells functions in calcium storage?

Sarcoplastic reticulum

Explanation:

The sarcoplastic reticulum is a structure found in muscle cells that stores calcium ions in skeletal muscles. They are made up of a network of smooth endoplasmic reticul (SER), that wrap around the myofibrils and help in transmitting electrical impulses that will determine whether the muscle will contract or not.

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.