The $ATPase$ enzyme required for muscle contraction is located on ..........

Which one of the following types of muscle fibers will be the first one to undergo fatigue?

Which of the following does not consist solely of involuntary muscles?

Rotation of the thigh on the lateral side is facilitated by:

Which of the following statements about the molecular arrangement of actin and myosin are correct?
$I.$ Each actin (thin filament) is made up of $2$ $F$ (filamentous) actins.
$II.$ $F$-actin is the polymer of $G$ (globular) actin.
$III.$ $2$ $F$-actins are twisted into a helix.
$IV.$ Two strands of tropomyosin (protein) lie in the grooves of $F$-actin.
The correct option is:

Proprioceptors are present in . . . . . . .