The storehouse of calcium ions in the muscle fibre is

The term $refractory$ $period$ with reference to muscle tissue refers to:

Skeletal muscles are closely associated with the $...A...$ components of the body. They have $... B...$ appearance under the microscope and hence are called $...C...$ muscles.
Choose the correct options to fill $A, B$ and $C$,so as to complete the given $NCERT$ statement.

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

Select the correct statement with reference to muscle structure.
$I.$ Each myosin is a polymerized protein.
$II.$ Many meromyosin constitute one thick filament (myosin).
$III.$ Each meromyosin's tail is called heavy meromyosin $(HMM)$ and head is called light meromyosin $(LMM)$.
$IV.$ The globular head is an active $ATPase$ enzyme and has binding sites for $ATP$ and active sites for actin.
Choose the option with correct statements.

The region between two successive $Z-$lines in a myofibril is