An individual sarcomere of a myofibril consists of:

The muscles that move the pinna (ear lobe) in rabbits are .....

Shivering with cold in winter is caused by

Give the name of the subunits of Troponin.

Which of the following statements are correct regarding skeletal muscle?
$A$. Muscle bundles are held together by a 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 the distribution pattern of actin and myosin proteins.
$D$. $M$ line is considered as the functional unit of contraction called sarcomere.
Choose the most appropriate answer from the options given below:

In a muscle fiber,$Ca^{++}$ is stored in the .....