The skeletal muscle organelles that actually contracts is (are) the:

A) sarcolemma.

B) sarcomere

C) transverse tubules.

D) myotubules.

E) myofibrils.

Answer: Option D.

Myofibrils.

Explanation:

Myofibrils are composed of thick and thin myofilaments that run parallel to each other to form muscle fibres in a striated muscles. They are made-up of repeating subunits called sacromeres.

The thin myofilaments.

Contraction of the striated muscles occur at the sacromeres. As the sacromere contracts, myofibrils contracts. When myofibrils contracts, the entire muscles contract.

Myofibrils.

Explanation:

Myofibrils may be defined as the basic unit of muscle cell that are rod like in appearances. The tubular like myocetes or muscle cells are present in the myofibrils.

Myofibrils consists of dark and light bands. The myofibril is the skeletal muscle organelle that actually contracts during the muscle contraction. The myofibril unit is formed during the embryonic development by the myogenesis process.

Thus, the correct answer is option (E).