Which muscle component is the smallest among the given options?

Match the following columns:

Column-$I$	Column-$II$
$P$. Skeletal muscle	$I$. Biceps
$Q$. Smooth muscle	$II$. Iris
$R$. Cardiac muscle	$III$. Heart

Which of the following statements correctly describes the type of muscle present in the specified body part?

$M-$line passes through the centre of

Which mineral element is essential for muscle contraction?

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: