What is the location of troponin in the process of muscle contraction?

What are $P, Q,$ and $R$ in the given diagram?
$P \quad\quad Q \quad \quad R$

Give the name of the subunits of Troponin.

The muscles that move the pinna (ear lobe) in rabbits are .....

During muscular contraction,which of the following events occur?
$(a)$ $'H'$ zone disappears
$(b)$ $'A'$ band widens
$(c)$ $'I'$ band reduces in width
$(d)$ Myosin hydrolyzes $ATP$,releasing the $ADP$ and $\Pi$
$(e)$ $Z$-lines attached to actins are pulled inwards
Choose the correct answer from the options given below.

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