The muscles immune to fatigue are

Muscles are red because of the presence of

Which of the following muscles act involuntarily?
$(a)$ Striated muscles $(b)$ Smooth muscles
$(c)$ Cardiac muscles $(d)$ Skeletal muscles

Cardiac muscle fibres are

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.

During muscle contraction: