The largest number of muscles in the human body is found in which region?

Identify the correct labels for the parts of the myosin monomer (meromyosin) shown in the diagram.

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 of the following ions is essential for muscular contraction?

Which of the following statements is correct regarding skeletal muscles?

Striated muscles contract by