Each Muscle Fiber is Almost Filled with Thread-Like Structures Called

Question

Each muscle fiber is almost filled with thread-like structures called _______.
A) fascicles
B) perimysium
C) myofibrils
D) actin

Accepted Answer

Myofibrils are the thread-like structures that fill each muscle fiber, and they are responsible for muscle contraction. Fascicles are groups of muscle fibers, perimysium is the connective tissue that surrounds fascicles, and actin is one of the two types of proteins that make up myofibrils.