Which of the following statements regarding contraction of a skeletal muscle fiber is true?

a) thick filaments shorten when muscle fibers contract.
b) some contractions occur without activation of myosin heads.
c) contracting muscle fibers do not always shorten.
d) contraction does not always require the occurrence of an action potential.
e) contraction only occurs following summation of action potentials from many motor neurons.

Contracting muscle fibers do not always shorten.

Explanation:

Skeletal muscle fibers may be defined as the fiber that contain the single muscle cell that is cylindrical in nature. The connective tissue present in muscle is epimysium.

The contraction of the skeletal muscle fiber helps in the movement of the body. The contraction of the muscle fiber do not means that the muscle fiber gets shorten. The thick and thin filaments remains in their original length and the sarcomere shortens only.

Thus, the correct answer is option (C).

its temperature is increasing. this causes molecular vibrations to increase.

high growth (apex)