Each muscle fiber is surrounded by a modified cell membrane called:

Explanation

The sarcolemma is the term used to describe the specialized cell membrane that surrounds each individual muscle fiber (also known as a muscle cell or myofiber). It is a modified plasma membrane that separates the intracellular contents of the muscle fiber from the extracellular environment. The sarcolemma is essential for maintaining the integrity and function of the muscle fiber, as it controls the movement of ions and molecules into and out of the cell, thereby regulating muscle cell excitability and contraction.