What is the full form of the following terms used in muscle structure?
$(1)$ $A$-disc
$(2)$ $I$-disc

The backward bending of the shank is worked out by

The sliding filament theory to explain muscular contraction was given by

Humerus and muscles are connected with

The "myosin binding site" is present on:

Arrange the following steps of muscle contraction in the sequence of events occurring first:
$I.$ Receptor sites on sarcolemma
$II.$ Nerve impulse
$III.$ Release of $Ca^{2+}$
$IV.$ Acetylcholine release
$V.$ Shortening of sarcomere
$VI.$ Synaptic cleft
$VII.$ Spread of impulse over sarcolemma on $T$-tubule
The correct option is: