The sarcoplasmic reticulum of skeletal muscle is a (a) form of smooth endoplasmic reticulum

The sarcoplasmic reticulum of skeletal muscle is a(a) form of smooth endoplasmic reticulum(b) site where calcium is released during muscle relaxation(c) site of calcium binding protein storage(d) Both (a) and (c)

Answer is : (d) The sarcoplasmic reticulum is a modified smooth ER that serves alternatively a storage site for cellular calcium, which are necessary for muscle contraction.