Which mineral element is essential for muscle contraction?

Which contractile protein of skeletal muscle is associated with $ATPase$ activity?

Arrange the given steps of muscle contraction in the series of events from first to last.
$I.$ Myosin head binds to the exposed active site on actin to form a cross bridge.
$II.$ The $Z$-line attached to these actin are also pulled inwards,thereby causing shortening of sarcomere,also called contraction.
$III.$ This pulls the attached actin filaments towards the centre of $A$-band.
The correct option is:

Which is the smallest muscle in the human body?

'Gastrocnemius' is a muscle of

Which characteristic is $NOT$ associated with white muscle fibers?