When we lift a heavy object,what happens to the muscles of the arm?

Define the sliding filament theory of muscle contraction.

Flexion of the thigh,knee,and their rotation is facilitated by:

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

What is the dark line lying in the middle of the $H$-zone called?

Which of the following statements are false regarding the muscle structure?
$I.$ In the centre of each $I$-band is an elastic fibre ($Z$-line) which bisects it.
$II.$ Thin filaments are firmly attached to the $Z$-line.
$III.$ $M$-line is a fibrous membrane in the middle of $A$-band.
$IV.$ $A$ sarcomere comprises one full $A$-band and two half $I$-bands.