Which of the following statements are correct regarding skeletal muscle?
A) Muscle bundles are held together by collagenous connective tissue layer called fascicle.
B) Sarcoplasmic reticulum of muscle fibre is a storehouse of calcium ions 
C) Striated appearance of skeletal muscle fibre is due to distribution pattern of actin and myosin filaments.
D) The portion of the myofibril between two successive ‘M’ lines is called sarcomere.
Choose the correct answer from the options given below.

Muscle bundles are held together by collagenous connective tissue layer called fascia.

A sarcomere is the basic structural and functional unit of a muscle. It is a highly organized structure found in both cardiac and skeletal muscle fibers. Sarcomeres are responsible for muscle contraction.

Each sarcomere is composed of overlapping thick and thin protein filaments. The thick filaments are made primarily of myosin, while the thin filaments are primarily composed of actin. During muscle contraction, these filaments slide past each other, causing the sarcomere to shorten. This sliding filament mechanism is the basis of muscle contraction and is regulated by calcium ions and various proteins within the sarcomere.